Civil   IjJ 


Engineering 
Library 


UNIVERSITY   OF  CALIFORNIA 

DEPARTMENT  OF  CIVIL   ENGINEERING 

BERKELEY,  CALIFORNIA 


ELECTRIC  WELDING 


ELECTRIC  WELDING 


BY 

ETHAN  VIALL 

EDITOR  AMERICAN  MACHINIST 

Member  American  Society  of  Mechanical  Engineers,  Society  of  Automotive  Engineers, 

American  Institute  of  Electrical  Engineers,  Franklin  Institute,  American  Welding 

Society.    Author  of  Manufacture  of  Artillery  Ammunition,  United  States 

Artillery  Ammunition,  United  States  Rifles  and  Machine  Guns, 

Broaches  and  Broaching,  Gas-Torch  and  Thermit  Welding. 


FIRST  EDITION 
THIRD  IMPRESSION 


McGRAW-HILL  BOOK  COMPANY,  INC. 

NEW  YORK:    370   SEVENTH  AVENUE 

LONDON:  6  &  8  BOUVERIE  ST.,  E.  C.  4 

1921 


.1          A 


Engineering 
Library 


l^U    l^jf^^ 

COPYRIGHT,  1921,  BY  THE 
McGRAW-HILL  BOOK  COMPANY,  INC 


PRINTED   IN   THE    UNITED    STATES    OF    AMERICA 


PREFACE 

Few  fields  afford  a  greater  opportunity  for  study  to  the 
mechanic,  the  student,  or  the  engineer,  than  that  of  electric 
welding.  Arc  welding,  with  its  practical,  every-day,  shop  appli- 
cations for  repair  and  manufacture,  is  in  some  respects  crowding 
closely  into  the  field  in  which  the  gas-torch  has  seemed  supreme. 
With  the  development  of  mechanical  devices  for  the  control  of 
the  arc,  the  range  of  application  to  production  work  has  greatly 
increased. 

Resistance  welding  presents  in  its  various  branches  some  of 
the  most  interesting  scientific  and  mechanical  problems  to  be 
found  anywhere.  Spot-welding — butt-welding — line-welding — 
all  occupy  a  particular  place  in  our  manufacturing  plants  today, 
and  new  uses  are  being  constantly  found. 

In  the  gathering  and  arranging  of  the  material  used  in  this 
book,  particular  care  has  been  taken  to  classify  and  place  various 
subjects  together  as  far  as  possible.  This  is  not  only  convenient 
for  reference  purposes,  but  enables  the  reader  to  easily  compare 
different  makes  and  types  of  apparatus.  In  most  cases,  the 
name  of  the  maker  of  each  piece  of  apparatus  is  mentioned 
in  the  description  in  order  to  save  the  time  of  those  seeking 
information. 

No  time  or  pains  have  been  spared  in  the  endeavor  to  make 
this  the  most  comprehensive  book  on  electric  welding  equipment 
and  practice,  ever  published.  Every  possible  source  of  informa- 
tion known  to  the  long-experienced  editor  has  been  drawn  upon 
and  properly  credited. 

It  is  hoped  that  this  book  will  prove  a  permanent  record  of 
electric  welding  as  it  is  today,  and  also  be  an  inspiration  and 
source  of  information  for  those  engaged  in  practice,  research 
or  development. 

ETHAN  VIALL. 

New  York  City, 
November,  1920. 


742296 


CONTENTS 


PAGE 

PREFACE v 

CHAPTER  I 

ELECTRIC  WELDING — HISTORICAL 1-    8 

The  Two  Classes  of  Electric  Welding — The  Zerner,  the  Ber- 
nardos,  the  Slavianoff,  the  Strohmenger-Slaughter  and  the 
LaGrange-Hoho  Processes — Early  Methods  of  Connecting  for 
Arc  Welding — Early  Resistance  Welding  Apparatus — First 
Practical  Butt-Welding  Device — DeBenardo  Spot-Welds — The 
Kleinschmidt  Apparatus — Bouchayer  's  Machine — Principle  of 
the  Harmatta  Patent — The  Taylor  Cross-Current  Spot-Welding 
Method. 

CHAPTER  II 

ARC  WELDING  EQUIPMENT 9-  27 

What  Electric  Arc-Welding  Is — Uses  of  B.C.  and  A.C. — 
Schematic  Layout  for  an  Arc- Welding  Outfit — Carbon  Electrode 
Process — Metallic  Electrode  Process — Selection  of  Electrodes — 
Relation  of  Approximate  Arc  Currents  and  Electrode  Diam- 
eters— Approximate  Current  Values  for  Plates  of  Different 
Thickness — Illustrations  of  the  Difference  Between  the  Carbon 
and  the  Metallic  Arc  Methods — Electrode  Holders — Sizes 'of 
Cable  for  Current — Face  Masks — Selecting  a  Welding  Outfit — 
Eye  Protection  in  Iron  Welding  Operations — The  Dangerous 
Rays — Properties  of  Various  Kinds  of  Glass. 

CHAPTER  III 

DIFFERENT  MAKES  OF  ARC  WELDING  SETS 28-  46 

General  Electric  Compound- Wound  Balancer-Type  Arc  Weld- 
ing Set — The  Welding  Control  Panel — Connections  for  G.E. 
Welding  Set — Data  for  Metallic-Electrode  Arc  Butt-  and  Lap- 
Welds — Carbon-Electrode  Cutting  Speeds — The  Wilson  Plastic- 
Arc  Set — Panel  for  Wilson  Welding  and  Cutting  Set — Wilson 
Portable  Outfit — The  Lincoln  Outfit — Westinghouse  Single- 

vii 


viii  CONTENTS 

PAGE 

Operator  Outfit — The  U.S.  Outfit — The  "Zeus"  Outfit — The 
Arcwell  Outfit — Alternating-Current  Arc-Welding  Apparatus — 
G.E.  Lead  Burning  Transformer. 

CHAPTER  IV 

TRAINING  ARC  WELDERS 47-  65 

Use  of  Helmets  and  Shields — The  Welding  Booth — Welding 
Systems — The  Electrode  Holder — Arc  Manipulation — Arc 
Formation — Fusion  of  Electrodes — Maintenance  of  Arc — 
Control  of  Arc  Travel — Weaving — Arc  and  Fusion  Character- 
istics— Polarity — Length  of  Arc — Stability — Overlap  and 
Penetration — Heat  Conductivity  and  Capacity — Expansion  and 
Contraction  of  Parent  Metal — Contraction  of  Deposited 
Metal — Welding  Procedure — Electrode  Current  Density — In- 
spection— Terminology. 

CHAPTER  V 
CARBON-ELECTRODE  ARC  WELDING  AND  CUTTING 66-  80 

Currents  Used  with  Carbon  Arc — Carbon  and  Graphite  Elec- 
trodes— Shapes  and  Size  of  Electrodes — Filler  Material — 
Proper  Welding  Position — Arc  Manipulation — Characteristics 
of  the  Arc — Polarity — Arc  Length — Building  up  Surfaces — 
Fused  Ends  of  Filler  Rods — Flanged  Seam  Welding — Weld- 
ing Non-Ferrous  Metals — Applications  of  Carbon-Arc  Weld- 
ing— Cutting — Data  on  Cutting  Steel  Plates — Cutting  Cast- 
iron  Plates — Cutting  Cast-Iron  Blocks. 

CHAPTER  VI 
ARC  WELDING  PROCEDURE 81-108 

Resume  of  Welding  Instructions — Filling  Sequence — Welding 
Two  Plates — The  Back-Step  Method — Welding  a  Square 
Patch — Quasi-Arc  Welding — Typical  Examples  of  Arc  Weld- 
ing— Examples  of  Tube  Work — Locomotive  Work — Welding 
Calculations — Strength  of  Welds — Stresses  in  Joints — Inspec- 
tion of  Metallic-Electrode  Arc- Welds— Good  and  Bad  Welds- 
Electrode  Diameters  for  Steel  Plate — Variation  in  Weld 
Strength  with  Change  in  Arc  Current — Effects  of  Short  and 
Long  Arcs — Heat  Treatment — Effects  of  the  Chemical  Com- 
position of  Electrodes — Physical  Characteristics  of  Plates — 
Chemical  Analysis  of  Specimens — The  Welding  Committees 
Electrodes. 


CONTENTS  ix 

CHAPTER  VII 

PAGE 

ARC  WELDING  TERMS  AND  SYMBOLS 109-126 

Definitions  of  Strap,  Butt,  Lap,  Fillet,  Plug  and  Tee  Welds — 
The  Single  V,  Double  V,  Straight,  Single  Bevel,  Double  Bevel, 
Flat,  Horizontal,  Vertical  and  Overhead  Weld — Tack,  Caulking, 
Strength,  Composite,  Reinforced,  Flush  and  Concave  Welds — 
Symbols  for  Various  Kinds  of  Welds. 

CHAPTER  VIII 

EXAMPLES  OF  ARC-WELDING  JOBS 127-170 

Work  on  the  German  Ships — Seventy  Cylinders  Saved  Without 
Replacement — The  Broken  Cylinders  of  the  George  Washing- 
ton— Cylinders  of  the  Pocahontas — General  Ship  Work — 
Locomotive  Work — Repair  on  a  Locomotive  Frame — Built-Up 
Pedestal  Jaw — Repaired  Drive  Wheel — Flue  and  Firebox 
Work — Side  Frames  and  Couplers — Amount  Saved  by  Weld- 
ing— Training  of  Welders — Welded  Rails  and  Cross-Overs — 
Built-Up  Rolling  Mill  Pods — Repaired  Mill  Housing — Welded 
Blow-Holes  in  Pulley — Method  of  Removing  Broken  Taps — 
Electric  Car  Equipment  Maintenance — A  Large  Crankshaft 
Repair — Welding  High-Speed  Tips  onto  Mild  Steel  Shanks — 
An  All- Welded  Mill  Building— Speed  of  Arc  Welding. 

CHAPTER  IX 

PHYSICAL  PROPERTIES  OF  ARC-FUSED  STEEL 171-190 

Preliminary  Examinations  of  Arc  Welds — Method  of  Prepar- 
ing Test  Specimens — Arrangement  of  the  Welding  Apparatus — 
The  ' '  Paste ' '  Used  for  Coated  Electrodes — Composition  of  Elec- 
trodes Before  and  After  Fusing — Relation  Between  Nitrogen- 
Content  and  Current  Density — Appearance  of  Specimens  After 
Test — Tensile  Properties  of  Electrodes — Results  of  Tests  on 
Fifty  Specimens — Mechanical  Properties  of  the  Are-Fused 
Metal — Dependence  of  Physical  Properties  on  Soundness — 
Macrostructure — Discussion  of  the  Results  of  the  Tests — Com- 
parison of  the  Bureau  of  Standards  and  the  Wirt-Jones  Tests. 

CHAPTER  X 

METALLOGRAPHY  OF  ARC-FUSED  STEEL 191-213 

General  Features  of  the  Microstructure  of  the  Electrodes 
Used — Microscopic  Evidence  of  Unsoundness — Characteristic 
"Needles"  or  "Plates" — Plates  Probably  due  to  Nitrates — 


X  CONTENTS 

PAGE 

Relation  of  Microstructure  to  the  Path  of  Rupture— Effect  of 
Heat  Treatment  Upon  Structure — Persistence  of  "Plates" 
After  Annealing — Thermal  Analysis  of  Arc-Fused  Steel — 
Summary. 

CHAPTER  XI 

AUTOMATIC  ARC  WELDING 214-238 

The  General  Electric  Automatic  Arc  Welding  Machine — The 
Welding  Head — Set-Up  for  Circular  Welding — Set-Up  for 
Building  Up  a  Shaft — Diagram  of  Control  of  Feed  Motor- 
Some  Work  Done  by  the  Machine — Repaired  Crane  Wheels — 
Welded  Hub  Stampings — Welded  Rear  Axle  Housings — Welded 
Tank  Seam — The  Morton  Semi-Automatic  Machine — Methods 
of  Mechanically  Stabilizing  and  Controlling  the  Arc — Examples 
of  Work  Done  by  the  Morton  Machine — The  G.E.  Electric- Arc 
Seam  Welding  Machine. 

CHAPTER  XII 

BUTT-WELDING  MACHINES  AND  WORK 239-275 

Resistance  Welding  Machines — Butt-Welding  Machines — Cur- 
rent Used  in  Butt-Welding — How  the  Secondary  Windings  of 
the  Transformer  are  Connected — Typical  Butt- Welding  Ma- 
chine with  Main  Parts  Named — How  the  Clamping  Jaws  are 
Operated — Annealing  Welds — Portable  Wire  Welding  Ma- 
chines— Examples  of  Butt-Welding  Jobs — Welding  Copper  and 
Brass  Rod — Welding  Aluminum — Typical  Copper  Welds — 
T-Welding — Welding  Band  Saws — Automobile  Rim  Welding — 
The  "  Flash- Weld  "—Welding  Heavy  Truck  Rims— Welding 
•  Pipe — The  Type  of  Clamp  Used  for  Pipe — The  Approximate 
Current  Used  for  Pipe  Welding — The  Winfield  Butt-Welding 
Machines— Cost  of  Butt- Welds— The  Federal  Butt-Welding 
Machines — Welding  Motor  Bars  to  the  End  Rings — Welding 
Valve  Elbows  on  Liberty  Motor  Cylinders — An  Automatic 
Chain-Making  Machine — Electro-Percussive  Welding — How  the 
Machine  is  Made — Uses  of  Percussive  Welding — Power  Con- 
sumed and  Time  to  Make  a  Percussive  Weld. 

CHAPTER  XIII 

SPOT- WELDING  MACHINES  AND  WORK 276-323 

Spot'- Welding — Three  Desirable  Welding  Conditions — Welding 
Galvanized  Iron  and  Other  Metals — Mash  Welding — Details  of 
Standard  Spot-Welding  Machines — Foot-,  Automatic-,  and 


•      CONTENTS  xi 

PAGE 

Hand-Operated  Machines — Examples  of  Spot-Welding  Work — 
Form  and  Sizes  of  Die-Points  for  Spot-Welding — The  Win- 
field  Spot-Welding  Machines — Machine  for  Welding  Auto- 
mobile Bodies— The  Federal  Spot-Welding  Machines — The 
Federal  Water-Cooled  Die-Points — Rotatable  Head  Two-Spot 
Welding  Machine — Automatic  Machine  for  Welding  Channels — 
Automatic  Pulley  Welding  Machine — The  Taylor  Cross-Cur- 
rent,  Spot-Welding  Machines — Automatic  Hog-Ring  Machine — 
A  Space-Block  Welding  Machine — Combination  Spot-  and 
Line-Welding  Machines — Spot-Welding  Machines  for  Ship 
Work — A  Large  Portable  Spot-Welding  Machine — Duplex 
Welding  Machine — A  Powerful  Experimental  Machine — 
Portable  Mash- Welding  Machine  for  Square  or  Round  Rods — 
Cost  of  Spot  Welding. 

CHAPTER  XIV 

WELDING  BOILER  TUBES  BY  THE  ELECTRIC  RESISTANCE  PROCESS.  . . .   324-342 

How  Boiler  Flues  are  Held  for  Welding — How  the  Tube 
Ends  are  Prepared— Scarf- Weld — Straight  Butt-Weld—Flash 
Weld — Use  of  a  Flux — How  the  Work  is  Placed  in  the  Jaws 
to  Heat  Evenly — Electric  and  Oil  Heating  Compared — Kind 
of  Machine  to  Use — Flash  Welding — Welding  in  the  Topeka 
Shops  of  the  Santa  Fe  Railroad — The  Way  the  Work  Heats 
Up— The  Final  Rolling. 

CHAPTER  XV 

ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL  AND  STELLITE  IN  TOOL 
MANUFACTURE 343-364 

The  Machines  Used  to  Weld  Tools— Welding  High-Speed  to 
Low-Carbon  Steel — Examples  of  Welded  Tools — Jaws  for 
Special  Work — How  the  Parts  are  Arranged  for  Welding — 
Clamping  in  the  Jaws — Insert  Welding — Jaws  for  Stellite 
Welding — Jaws  for  Stellite  Insert  Welding — The  Vertical  Type 
of  Welding  Machine — Making  a  ' '  Mash-Weld ' ' — Jaws  for 
Mash-Welding — Grooving  the  Pieces  to  be  Welded — Current 
Consumption  for  Various  Jobs — Sizes  of  Wire  to  Use. 

CHAPTER  XVI 

ELECTRIC  SEAM  WELDING 365-381 

The  Process  of  Seam  Welding — Kind  of  Machine  Used — De- 
tails of  the  Roller  Head — Thomson  Lap-Seam  Welding  Ma- 
chine— Welding  Oil  Stove  Burner  Tubes — Jig  for  Welding 


xii  CONTENTS 

PAGE 

Automobile  Muffler  Tubes — Jig  for  Welding  Large  Can 
Seams — Jig  for  Welding  Bucket  Bodies — Jig  for  Welding 
Ends  of  Metal  Strips  Together — Flange  Seam  Welding — Jig 
for  Welding  Teapot  Spouts — Approximate  Current  for  Six- 
Inch  Seam  for  Various  Thicknesses  of  Sheet  Metal — Size  of 
Wire  to  Use  in  Connecting  up  a  Welding  Machine. 

CHAPTER  XVII 

MAKING  PROPER  RATES  FOR  ELECTRIC  WELDING,  AND  THE  STRENGTH 
OF  WELDS 382-399 

Reasons  for  Misunderstanding  Between  User  and  Producer — 
The  Metering  Proposition — Energy  Consumption  of  Resistance 
Welding  for  Commercial  Grades  of  Sheet  Iron — Effect  of 
Clamping  Distance  Between  Electrodes  Upon  Time  and  Energy 
Demand — The  Load  Factor — Maximum  Demand — Power 
Factor — Strength  of  Combination  Spot  and  Arc  Welds — Spot 
Welding  Tests  on  Hoop  Iron — Strength  of  Spot-Welded 
Holes — Plates  Plugged  by  Welding — Tested  Plates — Tensile 
Tests  of  Plates  Plugged  by  Spot-Welding — Strength  of  Mash- 
Welded  Rods — Strength  of  Resistance  Butt-Welds — Elementary 
Electric  Information — What  is  a  Volt? — What  is  an  Ampere? 
—What  is  a  Kilowatt?— What  is  Kva? 


ELECTRIC  WELDING 


CHAPTER    I 
ELECTRIC  WELDING— HISTORICAL 

All  electric  welding  may  be  divided  into  two  general  classes 
— arc  welding  and  resistance  welding.  In  each  class  there  are 
a  number  of  ways  of  obtaining  the  desired  results.  Arc  welding 
is  the  older  process,  and  appears  to  have  been  first  used  by  de 
Meritens  in  1881  for  uniting  parts  of  storage  batteries.  He 
connected  the  work  to  the  positive  pole  of  a  current  supply 
capable  of  maintaining  an  arc.  The  other  pole  was  connected 
to  a  carbon  rod.  An  arc  was  struck  by  touching  the  carbon 
rod  to  the  work  and  withdrawing  it  slightly.  The  heat  generated 
fused  the  metal  parts  together,  the  arc  being  applied  in  a  way 
similar  to  that  of  the  flame  of  the  modern  gas  torch. 

Of  the  several  methods  of  arc  welding,  there  are  the  Zerner, 
the  Bernardos,  the  Slavianoff  and  the  Strohmenger-Slaughter 
processes,  as  well  as  some  modifications  of  them.  The  different 
methods  are  named  after  the  men  generally  credited  with  being 
responsible  for  their  development.  The  LaGrange-Hoho  process 
is  not  a  welding  process  at  all,  as  it  is  merely  a  method  of  heating 
metal  which  is  then  welded  by  hammering,  as  in  blacksmith 
work.  It  is  sometimes  called  the  " water-pail  forge." 

The  Zerner  process  employs  two  carbon  rods  fastened  in  a 
holder  so  that  their  ends  converge  like  a  V,  as  shown  in  Fig.  1. 
An  arc  is  drawn  between  the  converging  ends  and  this  arc  is 
caused  to  impinge  on  the  work  by  means  of  a  powerful  electro- 
magnet. The  flame  acts  in  such  a  manner  that  this  process  is 
commonly  known  as  the  electric  blowpipe  method.  The  Zerner 
process  is  so  complicated  and  requires  so  much  skill  that  it  is 
practically  useless.  A  modification  of  the  Zerner  process,  known 


-   >   %o<,  v 

"     i    O      S.   « 


2  ELECTRIC  WELDING 

as  t  be  ;'voltex  process,"  uses  carbon  rods  containing  a  small 
percentage  of  metallic  oxide  which  is  converted  into  metallic 
vapor.  iThris  vapor  increases  the  size  of  the  arc  and  to  some 
extent  prevents  the  excessive  carbonizing  of  the  work.  This 
process,  however,  is  about  as  impractical  for  general  use  as  the 
other. 

The  Bernardos  process  employs  a  single  carbon  or  graphite 


FlG.  1 The  Zerner  Electric  ' '  Blow-Pipe. : 


rod  and  the  arc  is  drawn  between  this  rod  and  the  work.  A 
sketch  of  the  original  apparatus  is  shown  in  Fig.  2.  This 
is  commonly  called  the  carbon-electrode  process.  In  using  this 
method  it  is  considered  advisable  to  connect  the  carbon  to  the 
negative  side  and  the  work  to  the  positive.  This  prevents  the 
carbon  of  the  rod  from  being  carried  into  the  metal  and  a  softer 
weld  is  produced. 

In  the  Slavianoff  process  a  metal  electrode  is  used  instead 


UNIVERSITY  OF  CALIFORNIA 
DEPARTMENT  OF  CIVIL   ENGINEERING 
ELECTRIC   WELDIN^H^^%IfA^AL|FOR(X:,|^ 

of  a  carbon.     This  process  is  known  as  the  metallic-electrode 
process. 

The  Strohmenger-Slaughter,  or  covered  electrode,  process 
is  similar  to  the  Slavianoff  except  that  a  coated  metallic  elec- 


"«<<(fffff'///^///&//&/S/////////////////////////W 

FIG.  2. — Original  Bernardos  Carbon  Electrode  Apparatus. 


Grid 
Rheostat 


Circuit 
Breaker, 


FIG.  3.— Arc  Welding  Circuits  as  First  Used. 

trode  is  used.  In  this  process  either  direct  or  alternating  cur- 
rent may  be  used. 

Some  of  the  early  methods  of  connecting  up  for  arc  welding 
are  shown  in  Fig.  3. 

The  LaGrange-Hoho  heating  process  makes  use  of  a  wooden 
tank  filled  with  some  electrolyte,  such  as  a  solution  of  sodium 


ELECTRIC  WELDING 


or  potassium  carbonate.  A  plate  connected  to  the  positive  wire 
is  immersed  in  the  liquid  and  the  work  to  be  heated  is  connected 
to  the  negative  wire.  The  work  is  then  immersed  in  the  liquid. 
When  the  piece  has  reached  a  welding  temperature  it  is  removed 
and  the  weld  performed  by  means  of  a  hammer  and  anvil 

Resistance  Welding. — The  idea  of  joining  metals  by  means 
of  an  electric  current,  known  as  the  resistance  or  incandescent 
process,  was  conceived  by  Elihu  Thomson  some  time  in  1877. 


JMMA/^^ 


FIG.  4.— First  Practical  Electric  Butt  Welding  Device,  Patented 
by  Elihu  Thomson,  Aug.  10,  1886. 

Little  was  done  with  the  idea  from  a  practical  standpoint  for 
several  years.  Between  1883  and  1885  he  developed  and  built 
an  experimental  machine.  A  larger  machine  was  built  in  1886. 
He  obtained  his  first  patent  on  a  device  for  electric  welding 
Aug.  10,  1886.  The  general  outline  of  this  first  device  is  shown 
in  Fig.  4.  The  first  experiments  were  mostly  confined  to  what 
is  now  known  as  butt  welding,  and  it  was  soon  found  that  the 
jaws  used  to  hold  the  parts  heated  excessively.  To  remedy  this 
water-cooled  clamping  jaws  were  developed. 


ELECTRIC   WELDING— HISTORICAL 


5 


FIG.  5.— Plates  "Spot  Welded"  by  Carbon  Arc. 


FIG.  6. — The  DeBenardo  Carbon  Electrode  Spot  Welding  Apparatus. 


FlG.  7. — The  Kleinschmidt  Apparatus,  Using  Copper  Electrodes. 


6  ELECTRIC   WELDING 

Closely  following  the  butt  welding  came  other  applications 
of  the  resistance  process,  such  as  spot,  point  or  projection,  ridge 
and  seam  welding.  Percussive  welding,  which  is  a  form  of 
resistance  welding,  was  developed  about  1905.  Since  spot  weld- 
ing is  such  an  important  factor  in  the  manufacturing  field  today 


FIG.  8. — Bouchayer's  Spot  Welding  Machine,  Using  Duplex  Copper 

Electrodes. 

the  evolution  of  this  process,  as  indicated  by  the  more  prominent 
patents,  will  be  of  considerable  interest:  Fig  5  shows  plates  spot 
welded  together  by  means  of  the  carbon  arc.  This  was  patented 
by  DeBenardo,  May  17,  1887,  Pat.  No.  363,320.  The  claims 
cover  a  weld  made  at  points  only.  The  darkened  places  indicate 


ELECTRIC  WELDING— HISTORICAL  7 

where  the  welds  were  made.  Fig.  6  shows  the  apparatus  made 
by  DeBenardo  for  making  "spot  welds,"  as  they  are  known 
today.  He  patented  this  in  Germany,  Jan.  21,  1888.  Carbon 
electrodes  were  used.  This  patent  was  probably  the  first  to 
cover  the  process  of  welding  under  pressure  and  also  for  passing 
the  current  through  the  sheets  being  welded.  The  German  patent 
number  was  46,776 — 49. 

The  apparatus  shown  in  Fig.  7  is  known  as  the  Kleinschmidt 
patent,  No.  616,463,  issued  Dec.  20,  1898.  The  patent  claims 
cover  the  first  use  of  pointed  copper  electrodes  and  raised  sec- 
tions, or  projections,  on  the  work  in  order  to  localize  the  flow 
of  the  current  at  the  point  where  the  weld  was  to  be  effected. 


\L 


FIG.  9. — Principle  of  the  Harmatta  Process,  Using  Copper  Electrodes. 


Considerable  pressure  was  also  applied  to  the  electrodes  and 
work  by  mechanical  means. 

Fig.  8  shows  diagrammatically  Bouchayer's  spot  welding 
machine,  patented  in  France,  March  13,  1903,  No.  330,200.  He 
used  two  transformers,  one  on  each  side  of  the  work.  Duplex 
copper  electrodes  were  used,  and  if  the  transformers  were  con- 
nected parallel  one  spot  weld  would  be  made  at  each  operation. 
If  the  transformers  were  connected  in  series  two  spot  welds 
would  be  made. 

Fig.  9  illustrates  the  principle  of  the  Harmatta  patent,  No. 
1,046,066,  issued  Dec.  3,  1912.  This  is  practically  the  same  as 
the  DeBenardo  patent,  No.  46,776 — 49,  except  that  copper  elec- 


8 


ELECTRIC  WELDING 


trodes  are  used.  However,  it  is  under  the  Harmatta  patent  that 
a  majority  of  the  spot  welding  machines  in  use  today  are  made. 
Fig.  10  illustrates  the  principle  on  which  the  Taylor  patent 
is  founded.  This  patent  was  issued  Oct.  16,  1917,  No.  1,243,004. 
It  covers  the  use  of  two  currents  which  are  caused  to  cross  the 
path  of  each  other  in  a  diagonal  direction,  concentrating  the 
heating  effects  at  the  place  of  intersection. 


a 

S 

b 

7 

FIG.  10. — The  Taylor  Cross-Current  Spot  Welding  Method. 

From  the  foregoing  it  will  be  seen  that  spot  welds,  as  this 
term  is  now  understood,  can  be  produced  in  a  number  of  ways, 
none  of  which  methods  are  identical.  As  a  matter  of  fact,  spot 
welds  can  be  produced  by  means  of  the  gas  torch  or  by  the 
blacksmith  forge  and  anvil,  although  these  methods  would  not 
be  economical. 


CHAPTER    II 
ARC  WELDING  EQUIPMENT 

Electric  Arc  Welding  is  the  transformation  of  electrical 
energy  into  heat  through  the  medium  of  an  arc  for  the  purpose 
of  melting  and  fusing  together  two  metals,  allowing  them  to 
melt,  unite,  and  then  cool.  The  fusion  is  accomplished  entirely 
without  pressure.  The  heat  is  produced  by  the  passage  of  an 
electric  current  from  one  conductor  to  another  through  air  which 
is  a  poor  conductor  of  electricity,  and  offers  a  high  resistance 
to  its  passage.  The  heat  of  the  arc  is  the  hottest  flame  that  is 
obtainable,  having  a  temperature  estimated  to  be  between 
3,500  and  4,000  deg.  C.  (6,332  to  7,232  deg.  P.). 

The  metal  to  be  welded  is  made  one  terminal  of  the  circuit, 
the  other  terminal  being  the  electrode.  By  bringing  the  elec- 
trode into  contact  with  the  metal  and  instantly  withdrawing  it 
a  short  distance,  an  arc  is  established  between  the  two.  Through 
the  medium  of  the  heat  thus  produced,  metal  may  be  entirely 
melted  away  or  cut,  added  to  or  built  up,  or  fused  to  another 
piece  of  metal  as  desired.  A  particularly  advantageous  feature 
of  the  electric  arc  weld  is  afforded  through  the  concentration 
of  this  intense  heat  in  a  small  area,  enabling  it  to  be  applied 
just  where  it  is  needed. 

Direct-current  is  now  more  generally  used  for  arc  welding 
than  alternating-current. 

When  using  direct-current,  the  metal  to  be  welded  is  made 
the  positive  terminal  of  the  circuit,  and  the  electrode  is  made  the 
negative  terminal. 

Regarding  alternating-current  it  is  obvious  that  an  equal 
amount  of  heat  will  be  developed  at  the  work  and  at  the  elec- 
trode, while  with  direct-current  welding  we  have  considerably 
more  heat  developed  at  the  positive  terminal.  Also  in  arc  weld- 
ing the  negative  electrode  determines  the  character  of  the  arc, 
which  permits  of  making  additions  to  the  weld  in  a  way  that  is 

9 


10 


ELECTRIC  WELDING 


not  possible  with  alternating-current.  Inasmuch  as  the  work 
always  has  considerably  greater  heat-absorbing  capacity  than  the 
electrode,  it  would  seem  only  reasonable  that  the  direct-current 
arc  is  inherently  better  suited  for  this  work. 

Two  systems  of  electric  arc  welding,  based  on  the  type  of 
electrode  employed,  are  in  general  use,  known  as  the  carbon  (or 
graphite)  and  the  metallic  electrode  processes.  The  latter 


Circuit 
Breaker 


rrn 


Grief 
Resistors 


Electrode 


Courtesy  of  the  Westinghouse  Co. 
FIG.  11. — Simple  Schematic  Welding  Circuit. 

process  is  also  sub-divided  into  those  using  the  bare  and  the 
covered  metallic  electrodes. 

A  simple  schematic  layout  for  an  arc-welding  outfit  is  shown 
in  Fig.  11. 

The  Carbon  Electrode  Process. — In  this  process,  the  nega- 
tive terminal  or  electrode  is  a  carbon  pencil  from  6  to  12  in. 
in  length  and  from  J  to  1£  in.  in  diameter.  This  was  the  original 
process  devised  by  Bernardos  and  has  been  in  more  or  less  general 


ARC  WELDING  EQUIPMENT  11 

use  for  more  than  thirty  years.  The  metal  is  made  the  positive 
terminal  as  in  the  metallic  electrode  process  in  order  that  the 
greater  heat  developed  in  this  terminal  may  be  applied  just 
where  it  is  needed.  Also,  if  the  carbon  were  positive,  the  tendency 
would  be  for  the  carbon  particles  to  flow  into  the  weld  and 
thereby  make  it  hard  and  more  difficult  to  machine. 

The  current  used  in  this  process  is  usually  between  300  and 
450  amp.  For  some  special  applications  as  high  as  from  600 
to  800  may  be  required,  especially  if  considerable  speed  is  desired. 
The  arc  supplies  the  heat  and  the  filler  metal  must  be  fed  into 
the  weld  by  hand  from  a  metallic  bar. 

The  class  of  work  to  which  the  carbon  process  may  be  applied 
includes  cutting  or  melting  of  metals,  repairing  broken  parts 
and  building  up  materials,  but  it  is  not  especially  adapted  to 
work  where  strength  is  of  prime  importance  unless  the  operator 
is  trained  in  the  use  of  the  carbon  electrode.  It  is  not  practical 
to  weld  with  it  overhead  or  on  a  vertical  surface  but  there  are 
many  classes  of  work  which  can  be  profitably  done  by  this  process. 
It  can  be  used  very  advantageously  for  improving  the  finished 
surface  of  welds  made  by  metal  electrodes.  The  carbon  electrode 
process  is  very  often  useful  for  cutting  cast  iron  and  non-ferrous 
metals,  and  for  filling  up  blowholes. 

The  Metallic  Electrode  Process. — In  the  metallic  electrode 
process,  a  metal  rod  or  pencil  is  made  the  negative  terminal, 
and  the  metal  to  be  welded  becomes  the  positive  terminal. 

When  the  arc  is  drawn,  the  metal  rod  melts  at  the  end  and 
is  automatically  deposited  in  a  molten  state  in  the  hottest  portion 
of  the  weld  surface.  Since  the  filler  is  carried  directly  to  the 
weld,  this  process  is  particularly  well  adapted  to  work  on  vertical 
surfaces  and  to  overhead  work. 

If  the  proper  length  of  arc  is  uniformly  maintained  on  clean 
work,  the  voltage  across  the  arc  will  never  greatly  exceed  22 
volts  for  bare  electrodes  and  35  volts  for  coated  electrodes.  The 
arc  length  will  vary  to  a  certain  degree  however,  owing  to  the 
physical  impossibility  of  an  operator  being  able  to  hold  the  elec- 
trode at  an  absolutely  uniform  distance  from  the  metal  through- 
out the  time  required  to  make  the  weld. 

It  is  very  essential  that  the  surfaces  be  absolutely  clean  and 
free  from  oxides  and  dirt,  as  any  foreign  matter  present  will 
materially  affect  the  success  of  the  weld. 


12  ELECTRIC  WELDING 

When  using  a  metallic  electrode,  the  arc  which  is  formed 
by  withdrawing  it  from  the  work,  consists  of  a  highly  luminous 
central  core  of  iron  vapor  surrounded  by  a  flame  composed 
largely  of  oxide  vapors.  At  the  temperature  prevailing  in  the 
arc  stream  and  at  the  electrode  terminals,  chemical  combinations 
occur  instantaneously  between  the  vaporized  metals  and  the 
atmospheric  gases.  These  reactions  continue  until  a  flame  of 
incandescent  gaseous  compounds  is  formed  which  completely 
envelopes  the  arc  core.  However,  drafts  created  by  the  high 
temperature  of  the  vapors  and  by  local  air  currents  tend  to 
remove  this  protecting  screen  as  fast  as  it  is  formed,  making  it 
necessary  for  the  welder  to  manipulate  the  electrode  so  that  the 
maximum  protective  flame  for  both  arc  stream  and  electrode 
deposit  is  continuously  secured.  This  can  be  obtained  auto- 
matically by  the  maintenance  of  a  short  arc  and  the  proper 
inclination  of  the  electrode  towards  the  work  in  order  to  com- 
pensate for  draft  currents. 

Selection  of  Electrodes. — The  use  of  a  metallic  electrode 
for  arc  welding  has  proved  more  satisfactory  than  the  use  of 
a  carbon  or  graphite  electrode  which  necessitates  feeding  the 
new  metal  or  filler  into  the  arc  by  means  of  a  rod  or  wire.  The 
chief  reason  for  this  is  that,  when  the  metallic  electrode  process 
is  used,  the  end  of  the  electrode  is  melted  and  the  molten  metal 
is  carried  through  the  arc  to  be  deposited  on  the  material  being 
welded  at  the  point  where  the  material  is  in  a  molten  state 
produce*!  by  the  heat  of  the  arc.  Thus  a  perfect  union  or  fusion 
is  produced  with  the  newly  deposited  metal. 

Wire  for  metallic  arc  welding  must  be  of  uniform,  homogene- 
ous structure,  free  from  segregation,  oxides,  pipes,  seams,  etc. 
The  commercial  weldability  of  electrodes  should  be  determined 
by  means  of  tests  performed  by  an  experienced  operator,  who 
can  ascertain  whether  the  wire  flows  smoothly  and  evenly  through 
the  arc  without  any  detrimental  phenomena. 

The  following  table  indicates  the  maximum  range  of  the 
chemical  composition  of  bare  electrodes  for  welding  mild  steel: 

Carbon  trace  up  to 0.25% 

Manganese  trace  up  to 0.99% 

Phosphorous  not  to   exceed 0.05% 

Sulphur  not  to  exceed 0.05% 

Silicon  not  to  exceed 0.08% 


ARC   WELDING  EQUIPMENT 


13 


The  composition  of  the  mild  steel  electrodes,  commonly  used, 
is  around  0.18  per  cent  carbon,  and  manganese  not  exceeding 
0.05  per  cent,  with  only  a  trace  of  phosphorus,  sulphur  and 
silicon. 

The  size,  in  diameter,  ordinarily  required  will  be  1/8  in.,  5/32 
in.,  and  Vie  in-  an<l  only  occasionally  the  3/32  in- 

These  electrodes  are  furnished  by  a  number  of  firms,  among 
whom  are  John  A.  Roebling's  Sons  Co.,  Trenton,  N.  J. ;  American 
Rolling  Mills  Co.,  Middlctown,  Ohio ;  American  Steel  and  Wire 


50 


£00 


250 


100  150 

Amperes   Arc  Current 

Courtesy  of  the  Westinghouse  Co. 

FIG.  12. — Eelation  of  Approximate  Arc  Currents  and  Electrode  Diameters. 

Co.,  Pittsburgh;  Ferride  Electric  Welding  Wire  Co.,  New 
York  City ;  Page  Woven  Wire  Co.,  Monessen,  Pa. ;  John  Potts 
Co.,  Philadelphia.  (M**  ) 

A  coated  electrode  is  one  which  has  had  a  coating  of  some 
kind  applied  to  its  surface  for  the  purpose  of  totally  or  partially 
excluding  the  atmosphere  from  the  metal  while  in  a  molten  state 
when  passing  through  the  arc  and  after  it  has  been  deposited. 

The  proper  size  of  electrode  may  be  determined  from  Fig. 
12  from  which  it  will  be  seen  that  the  class  of  work  and  current 
used  are  both  factors  determining  the  size  of  the  electrode  for 


14  ELECTRIC  WELDING 

welding  steel  plates  of  various  i  hicknesses.  To  find  the  diameter 
of  the  metallic  electrode  required,  select,  for  example,  a  three- 
eighths  plate,  and  follow  horizontally  to  the  "Thickness  of  the 
Plate  Curve/'  The  vertical  line  through  this  intersection  repre- 
sents about  110  amp.  as  the  most  suitable  current  to  be  used 
with  this  size  of  plate.  Then  follow  this  vertical  line  to  its 
intersection  with  the  "Diameter  of  Electrode"  curve  which 
locates  a  horizontal  line  representing  approximately  an  electrode 
5/32  in.  in  diameter.  In  a  similar  manner,  a  V^-in.  plate  requires 
about  125  amp.  and  a  5/32-in.  electrode. 

The  amount  of  current  to  be  used  is  dependent  on  the  thick- 
ness of  the  plate  to  be  welded  when  this  value  is  J  in.  or  less. 
Average  values  for  welding  mild  steel  plates  with  direct  current 
are  indicated  by  the  curve  referred  to  above  in  connection  with 
the  selection  of  the  electrode  of  proper  size.  These  data  are  also 
shown  in  Table  I. 

TABLE     I. — APPROXIMATE    CURRENT    VALUES    FOR    PLATES    OF    DIFFERENT 

THICKNESS 


Plate  Thickness 

Current 

Electrode  Diameter 

in  Inches 

in  Amperes 

in  Inches 

1/16 

20  to     50 

1/16 

1/8 

50  to     85 

3/32 

3/16 

75  to  110 

1/8 

1/4 

90  to  125 

1/8 

3/8 

110  to  150 

5/32 

1/2 

125  to  170 

5/32 

5/8 

140  to  185 

5/32 

3/4 

150  to  200 

3/16 

7/8 

165  to  215 

3/16 

1 

175  to  225 

3/16 

It  should  be  borne  in  mind,  however,  that  these  values  are 
only  approximate  as  the  amount  of  current  to  be  used  is 
dependent  on  the  temperature  of  the  plate  and  also  upon  the 
type  of  joint.  For  example,  when  making  a  lap  weld  between 
two  |-in.  steel  plates  at  ordinary  air  temperature  of  about 
65  deg.  F.  it  has  been  found  that  the  extra  good  results  were 
obtained  by  using  a  current  of  about  225  amp.  and  a  Vie-in  • 
diameter  electrode.  The  explanation  for  the  high  current  per- 
missible is  the  tremendous  heat  storage  and  dissipation  capacity 
of  the  lapped  plates  which  makes  the  combination  practically 


ARC  WELDING  EQUIPMENT 


15 


FIG.  13.— Carbon-Arc  Welding,  Using  King  Mask. 


FlG.  14. — Metallic-Arc  Welding,  Using  a  Hand  Shield. 


16 


ELECTRIC  WELDING 


equivalent  to  that  of  a  butt  weld  of  two  1-in.  plates.  For  that 
reason  the  above  values  will  be  very  greatly  increased  in  the 
case  of  lap  welds  which  require  practically  twice  the  amount 
of  current  taken  by  the  butt  welds. 

When  the  proper  current  value  is  used  there  will  be  a  crater, 


FIG.  15. — Simple  Form  of  Electrode  Holder. 

or  depression,  formed  when  the  arc  is  interrupted.  This  shows 
that  the  newly  deposited  metal  is  penetrating  or  "biting  into" 
the  work. 

The  difference  between  the  carbon  and  the  metallic  electrode 
processes  can  be  seen  in  Figs.  13  and  14.    In  Fig.  13  the  welder 


FIG.  16. — Special  Make  of  Electrode  Holder. 

is  using  a  carbon  electrode  and  feeding  metal  into  the  weld  from 
a  metal  rod  held  in  his  left  hand.  In  Fig.  14  the  metal  rod 
is  held  in  a  special  holder  and  not  only  carries  the  current  but 
metal  from  it  is  deposited  on  the  work. 

Electrode  holders  should  be  simple,  mechanically  strong,  and 
so  designed  as  to  hold  the  electrode  firmly.     It  should  be  prac- 


ARC  WELDING  EQUIPMENT  17 

tically  impossible  to  burn  or  damage  the  holder  by  accidental 
contact  so  that  it  will  not  work.  Small,  flimsy  or  light  projecting 
parts  are  almost  sure  to  be  broken  off  or  bent.  Fig.  15  shows 
one  of  these  holders  that  answers  the  requirements.  However, 
any  of  the  companies  selling  arc  welding  apparatus  will  be  able 
to  supply  dependable  holders. 

A  holder  made  by  the  Arc  Welding  Machine  Co.,  New  York, 
is  shown  in  Fig.  16  and  in  detail  in  Fig.  17.  The  metal  rod 
is  clamped  in  by  means  of  an  eccentric  segment  operated  by 
a  thumb  lever.  If  the  rod  should  freeze  to  the  work  it  will  not 
pull  out  of  the  holder,  but  will  be  gripped  all  the  tighter.  The 


FIG.  17. — Details  of  Special  Electrode  Holder. 

welding  current  enters  at  the  rear  end  of  the  composition  shank, 
passes  along  the  shank  to  the  head  of  the  tool,  and  from  there 
directly  into  the  electrode.  It  will  be  noted  that  there  are  no 
joints  in  this  tool  except  where  the  cable  is  soldered  into  the 
shank.  There  is  a  relatively  large  contact  surface  between  the 
electrode  and  the  holding  head,  which  precludes  any  possible 
heating  at  this  point.  The  trigger  is  intended  for  remote  control 
employed  with  the  closed  circuit  system.  Whenever  this  holder 
is  used  on  other  systems,  the  trigger  is  omitted. 

Cable. — For  arc  welding  service  the  cables  leading  to  the 
electrode  holder  should  be  very  flexible  in  order  to  allow  the 
operator  full  control  of  the  arc. 

The  following  sizes  of  cable  have  been  found  by  the  General 


18 


ELECTRIC  WELDING 


Electric  Co.    suitable  for  this  service,  due  account  being  taken 
of  the  intermittent  character  of  the  work. 

It  is  extra  flexible  stranded  dynamo  cable,  insulated  for  75-v. 
circuit,  with  varnished  cambric  insulation,  covered  with  weather- 
proof braid. 

Circular  Mills 
90,000 

150,000 
260,000 

It  will  be  noted  in  Figs.  13  and  14,  that  two  different  ways 
of  protecting  the  eyes  are  shown.  One  man  has  a  helmet  and 


Amperes 

Size  of  Cable 

Up  to  200 

225/24 

Over  200 
Up  to  500 

375/24 

Over  500 
Up  to  1,000 

650/24 

FIG.  18. — King  Face  Masks  With  and  Without  Side  Screens. 

the  other  uses  a  shield  held  in  the  hand.  Conditions  under  which 
the  welders  work,  and  their  personal  preferences,  largely  dictate 
which  type  is  to  be  used.  However,  no  welder  should  ever  at- 
tempt arc  welding  without  a  protecting  screen  fitted  with  the 
right  kind  of  glass.  Cheap  glass  is  dear  at  any  price,  for  the 
light  rays  thrown  off  from  the  arc  are  very  dangerous  to  the 
eyesight.  The  guard  should  be  so  made  as  to  not  only  protect 
the  eyes  from  dangerous  light  rays,  but  should  also  protect  the 
face  and  neck  from  flying  sparks  of  metal. 

A  very  good  face  mask  made  by  Julius  King  Optical  Co., 
New  York,  is  shown  in  Fig.  18.     These  masks  are  made  of  fiber 


ARC  WELDING  EQUIPMENT 


19 


and  provision  is  made  for  a  free  circulation  of  air  between  the 
front  and  the  face,  not  only  keeping  the  operator  cool,  but 
preventing  the  tendency  of  the  lenses  to  fog.  The  masks  are 
supported  by  bands  over  the  head  and  it  is  said  that  weight 


FIG.  19. — King  Hand  Shields. 


Fie.  20. — Method  of  Using  Screens  to  Protect  Others. 

is  not  apparent  and  that  they  are  as  comfortable  to  wear  as  a 
cap.  Two  styles  are  made — with  and  without  side  screens.  The 
one  without  screens  may  be  had  with  combination  lenses  tinted 
for  acetylene  or  electric  welding  or  with  any  other  tint  for 
specific  work.  The  one  with  side  screens,  providing  side  vision, 


20 


ELECTRIC  WELDING 


ARC   WELDING  EQUIPMENT  21 

is  fitted  either  with  combination  lenses  or  with  Ciear  Saniglass 
lenses.  A  hand  shield  is  shown  in  Fig.  19. 

In  arc  welding  in  the  open,  other  workmen  or  onlookers  are 
liable  to  injury  as  well  as  the  welders,  so  screens  should  be  placed 
around  the  work  to  conceal  the  light  rays  from  the  view  of 
others  besides  the  welder.  Such  an  arrangement  is  shown  in 
Fig.  20. 

Where  repetition  work  is  to  be  done,  it  is  well  to  provide 
individual  stalls  or  booths,  somewhat  similar  to  the  one  shown 
in  Fig.  21.  These  were  designed  for  use  in  the  welding  schools 
under  the  supervision  of  the  Lincoln  Electric  Co.  For  actual 
shop  work,  curtains  or  screens  should  be  provided  back  of  the 
welders. 

It  must  be  remembered  also,  that  owing  to  the  presence  of 
ultra-violet  rays,  severe  flesh  burns  may  result  with  some  people 
if  proper  gloves  and  clothing  are  not  worn — especially  when 
using  the  carbon  arc. 

Selecting  a  Welding  Outfit. — Welding  outfits  may  be  of  the 
stationary  or  the  portable  type.  These  may  also  be  divided  into 
motor-generator  sets  and  the  "transformer"  types.  Both  d.c. 
and  a.c.  current  may  be  used  primarily,  depending  on  the  ap- 
paratus employed  and  the  source  of  current  available. 

Regarding  the  selection  of  any  particular  outfit  J.  M.  Ham, 
writing  in  the  General  Electric  Review  for  December,  1918,  says : 

Few  things  electrical  have  in  so  short  a  period  of  time 
created  such  wide-spread  interest  as  that  of  arc  welding.  En- 
gineers having  to  do  with  steel  products,  in  whatever  form 
produced  or  in  whatever  way  employed,  have  investigated  its 
uses  not  only  as  a  building  agent  when  applied  to  new  material 
but  as  a  reclaiming  agent  for  worn  or  broken  parts.  In  both 
cases  its  possibilities  as  a  means  of  greatly  increasing  output 
and  in  saving  otherwise  useless  parts  at  a  small  fraction  of  their 
original  or  replacement  value  has  proved  astounding. 

Out  of  these  investigations  have  grown  several  systems  of 
arc  welding. 

To  exploit  these  is  the  duty  of  the  sales  department  and  the 
measure  of  its  success  depends  upon  the  quality  of  service 
rendered. 

The  difficulties  of  giving  service  are  perhaps  not  fully  ap- 
preciated. Where  so  many  systems  have  been  called  for  and 


22  ELECTRIC   WELDING 

where  so  many  individual  ideas  have  to  be  met,  the  problems 
of  the  manufacturer  become  multiplied. 

During  a  period  of  freight  congestion  when  locomotives  were 
in  unprecendented  demand,  an  engine  was  run  into  the  repair 
shop  with  slid  flat  spots  on  each  of  the  eight  driving  wheels, 
and  orders  were  issued  to  return  it  ready  for  service  in  record 
time.  In  three  hours  repairs  had  been  completed  by  means  of 
the  electric  arc  (to  have  put  on  new  tires  would  have  required 
three  to  four  days)  and  the  locomotive  was  out  on  the  road. 
Many  other  achievements  as  remarkable  as  these  have  been 
obtained. 

It  would  seem  that  having  demonstrated  the  success  of  arc 
welding  for  a  given  line  of  work,  others  similarly  engaged 
would  be  keen  to  take  advantage  of  it ;  but  that  is  true  only 
in  part,  possibly  because  this  is  a  "show  me"  age. 

When  it  becomes  apparent  to  the  investigator  of  arc  welding 
possibilities  that  the  process  fulfills  his  requirements,  the  ques- 
tion of  what  system  to  employ  confronts  him;  salesmen  are  on 
the  job  to  tell  bin*  about  their  particular  specialties.  He  is 
informed  that  the  real  secret  of  welding  is  having  the  proper 
electrode  (the  salesman's  special  kind)  ;  it  must  be  covered  or 
bare,  as  the  case  may  be,  and  contain  certain  unnamed  in- 
gredients. The  merits  of  the  direct-current  system  are  extolled. 
Alternating-current  outfits  are  advocated  by  others,  it  being 
claimed  that  they  bite  deeper  and  weld  if  the  arc  is  held.  The 
prospective  buyer  retires  with  a  headache  to  think  it  over. 

There  is  no  mystery  about  arc  welding.  It  is  being  done 
with  all  sorts  of  outfits  and  many  varieties  of  electrodes.  It 
can  even  be  done  from  power  lines  with  resistance  in  series  with 
the  arc.  But  these  systems  differ  widely  in  essentials,  just  as 
in  the  case  of  automobiles.  We  can  buy  a  cheap  car  or  an 
expensive  car,  and  in  either  event  we  get  just  about  what  we 
pay  for. 

The  arc-welding  set  must  pay  its  way.  It  must  earn  dividends 
and  conserve  materials,  and  when  properly  selected  and  applied 
does  both  of  these  things  to  a  degree  quite  gratifying.  To  the 
discriminating  purchaser  it  is  not  sufficient  merely  to  know  that 
an  outfit  will  make  a  weld,  he  wants  to  know  if  it  is  the  best 
weld  that  can  be  made,  if  it  can  be  made  in  the  shortest  possible 
time,  and  whether  the  ratio  between  cost  of  the  entire  system 


ARC  WELDING  EQUIPMENT  23 

to  the  savings  affected  is  the  lowest  obtainable.  He  doubtless 
will,  if  the  work  is  of  sufficient  magnitude  to  warrant,  establish 
a  welding  department  with  a  trained  arc  welding  man  in  charge, 
and  see  that  this  department  stands  on  its  own  feet.  By  so  doing 
he  places  responsibility  on  a  man  who  knows  what  to  do  and 
how  to  do  it — a  friend  rather  than  a  foe  of  the  system.  He 
will,  other  things  being  anything  like  equal,  respect  the  opinion 
of  the  operator  in  the  selection  of  the  system  to  be  employed, 
because  it  is  better  to  provide  a  man  with  tools  he  is  familiar 
with  and  prefers  to  use,  rather  than  to  force  him  to  use  some- 
thing with  which  he  is  unfamiliar  or  which  he  regards  with 
disfavor. 

Obviously,  the  purchaser  wishes  to  know  that  the  companies 
he  is  dealing  with  are  reliable  and  responsible,  that  the  experience 
back  of  the  salesmen  is  sufficient  to  warrant  faith  in  his  product. 
It  is  important  to  know  the  amount  of  power  required  per 
operator  and  whether  drawing  the  needed  amount  from  his  own 
lines  or  from  those  of  the  power  company  will  interfere  with 
the  system,  and  if  so  to  what  extent,  and  what,  if  any,  additional 
apparatus  will  be  needed  to  correct  the  trouble.  Having 
determined  these  things  to  his  satisfaction,  he  can  install  his 
arc-welding  system  with  a  considerable  degree  of  assurance  that 
there  will  be  a  decided  saving  in  time,  men,  and  money,  and  a 
genuine  conservation  of  materials. 

EYE    PROTECTION    IN   IRON    WELDING    OPERATIONS 

In  the  General  Electric  Review  for  Dec*,  1918,  W.  S.  Andrews 
says  in  part: 

Radiation  from  an  intensely  heated  solid  or  vapor  may  be  divided  under 
the  three  headings: 

(1)  Invisible  infra-red  rays 

(2)  Visible  light  rays 

(3)  Invisible  ultra-violet  rays. 

There  is  no  clear  line  of  demarcation  between  these  divisions,  as  they 
melt  gradually  one  into  the  other  like  the  colors  of  the  visible  spectrum. 
When  the  heated  matter  is  solid,  such  as  the  filament  of  an  incandescent 
lamp,  the  visible  spectrum  is  usually  continuous,  that  is,  without  lines  or 
bands;  but  when  it  is  in  the  form  of  a  gas  or  vapor,  as  in  the  iron  arc 
used  for  welding  operations,  the  spectrum  is  divided  up  into  bands  or  ia 
crossed  by  lines  which  are  characteristic  of  the  element  heated. 


24  ELECTRIC  WELDING 

The  radiations  under  the  foregoing  three  headings,  although  of  common 
origin,  produce  very  diverse  effects  upon  our  senses.  Thus,  the  infra-red 
rays  produce  the  sensation  of  heat  when  they  fall  on  our  unprotected  skin, 
but  they  are  invisible  to  our  eyes.  The  visible  light  rays  enable  us  to 
see;  but  we  have  no  sense  that  perceives  the  ultra-violet  rays,  so  that  we 
know  of  them  only  by  their  effects. 

The  intense  glare  emitted  in  the  process  of  arc  welding  consists  of 
a  combination  of  all  these  rays,  and  special  safety  devices  are  required  to 
protect  the  operator  from  their  harmful  effects. 

For  welding  with  acetylene  and  for  light  electric  welding,  it  may  be 
necessary  only  to  protect  the  eyes  with  goggles  fitted  with  suitable  colored 
glasses. 

A  hand  shield  made  of  light  wood,  and  which  has  a  safety  colored 
glass  window  in  the  center  is  also  sometimes  used.  This  device  is  used 
for  medium  weight  electric  welding  done  with  one  hand.  The  shield  serves 
the  double  purpose  of  protecting  the  eyes  of  the  operator  and  also  shielding 
his  face  from  the  heat  rays  and  the  ultra-violet  radiation,  which  might 
otherwise  cause  a  severe  sunburn  effect. 

For  heavy  electric  welding,  which  requires  the  use  of  both  hands, 
it  is  common  practice  for  the  operator  to  protect  his  eyes  and  neck  with 
a  helmet  fitted  with  a  round  or  rectangular  window  of  safety  glass.  These 
helmets  are  usually  made  of  some  strong  light  material  such  as  vulcanized 
fiber  and  are  designed  so  that  they  can  be  slipped  on  and  off  easily, 
the  weight  resting  on  the  shoulders  of  the  operator. 

There  are  a  great  many  different  kinds  of  special  safety  glasses  on 
the  market,  and  many  combinations  of  ordinary  colored  glass  are  also 
in  common  use,  so  a  brief  discussion  of  this  very  important  subject  is 
in  order. 

It  is  well  known  that  the  normal  human  eye  shows  considerable  chromatic 
aberration  towards  the  red  and  blue-violet  ends  of  the  spectrum  and  that 
this  defect  is  completely  corrected  in  regard  to  the  middle  colors.  It, 
therefore,  naturally  follows  that  a  much  clearer  definition  of  an  object 
is  obtained  by  combinations  of  yellow-green  light  than  by  red  alone,  or 
especially  by  blue  or  violet  light  alone.  The  eye  is  also  more  sensitive 
to  the  yellow  and  green  rays  than  it  is  to  the  red  and  blue  rays;  or  in 
other  words,  yellow-green  light  has  the  highest  luminous  efficiency.  This 
may  easily  be  verified  by  looking  at  a  sunlit  landscape  or  fleecy  clouds 
in  a  blue  sky  through  plates  of  different  colored  glass.  A  glass  of  a  light 
amber  color  or  amber  slightly  tinted  with  green  will  clearly  bring  out 
details  that  are  hardly  observable  without  the  glass,  and  which  will  be 
obscured  entirely  by  a  blue  or  violet  glass.  It  is  therefore  obvious  that  in 
order  to  obtain  the  clearest  definition  or  visibility  with  the  least  amount 
of  glare,  the  selection  of  the  color  tint  in  safety  glasses  should  properly 
be  decided  by  an  expert;  but  the  depth  of  tint  or,  in  other  words,  the 
amount  of  obscuration  may  be  determined  best  by  the  operator  himself, 
owing  to  the  individual  difference  in  visual  acuity  which  will  permit  one 
man  to  see  clearly  through  a  glass  that  would  be  too  dark  for  another  man. 

When  the   invisible  infra-red   rays  encounter  any  material  which  they 


ARC  WELDING  EQUIPMENT  25 

cannot  penetrate,  or  which  is  opaque  to  them,  they  are  absorbed  and  are 
changed  into  heat.  Hence,  they  are  frequently  termed  heat  rays.  It  is, 
therefore,  very  necessary  to  guard  the  eyes  from  these  rays;  and  although 
they  are  absorbed  to  a  certain  extent  by  ordinary  colored  glass,  this  is 
not  sufficient  protection  against  any  intense  source.  There  are,  however, 
several  kinds  of  glass,  which,  although  fairly  transparent  to  visible  light, 
are  wonderfully  efficient  in  absorbing  heat.  The  effects  of  even  low-power 
heat  rays,  when  generated  in  close  proximity  to  the  eyes  for  considerable 
time,  are  often  serious,  as  is  evidenced  by  the  fact  that  glass  blowers, 
who  use  their  unprotected  eyes  near  to  hot  gas  flames  of  weak  luminous 
intensity,  are  frequently  afflicted  with  cataract  which  might  be  positively 
avoided  by  wearing  properly  fitted  spectacles. 

In  selecting  colored  glasses,  great  care  should  be  taken  to  discard  all 
samples  that  show  streaks  or  spots,  as  these  defects  are  liable  to  produce 
eye-strain.  The  glass  should  be  uniform  in  color  and  thickness  throughout, 
and  the  colored  plate  should  be  protected  from  outside  injury  by  a  thin 
piece  of  clear  glass  that  can  easily  be  renewed. 

Table  II  indicates  roughly  the  percentage  of  heat  rays  transmitted 
by  various  colored  glasses  of  given  thickness.  The  source  of  heat  used 
was  a  200-watt,  gas-filled  Mazda  lamp  operating  at  a  temperature  of  about 
2400  deg.  C.  Although  the  figures  are  substantially  correct  for  the  samples 
tested,  they  would  necessarily  vary  somewhat  for  other  samples  of  different 
thickness  and  degrees  of  coloration,  so  that  they  can  be  taken  only  as  a 
general  guide  for  comparative  purposes.  Examination  of  the  table  will 
show  that  the  last  three,  or  commercial  samples,  all  show  better  than  90 
per  cent  exclusion  of  the  heat  rays. 

TABLE  II. — QUALITIES  OF  VARIOUS  KINDS  OF  GLASS 

Per  Cent 

Thickness  Heat  Rays 

in  Inches  Trans- 

Kind  of  Glass  mitted 

Clear  white  mica 0.004  81 

Clear  window  glass 0.102  74 

Flashed  ruby    0.097  69 

Belgium  pot  yellow 0.126  50 

Cobalt  blue   0.093  43 

Emerald  green 0.100  36 

Dark   mica    0.007  15 

Special  light  green  glass 0.09.5  10 

Special  dark  glass 0.096  4 

Special  gold-plated  glass 0.114  0.8 

As  to  the  invisible  ultra-violet  rays,  they  are  principally  to  be  feared 
not  only  because  they  are  invisible,  but  because  we  have  no  organ  or 
sense  for  detecting  them,  and  we  can  only  trace  their  existence  by  their 
effects.  In  all  cases,  however,  when  we  are  forewarned  of  their  presence, 
they  are  very  easily  shielded,  for  there  are  only  a  few  substances  which 


26  ELECTRIC  WELDING 

are  transparent  both  to  visible  light  and  to  ultra-violet  radiation.  Foremost 
among  these  latter  substances,  because  it  is  most  common,  is  clear  natural 
quartz  or  rock  crystal,  from  which  the  so-called  "pebble"  spectacle  lenses 
are  made.  Fluorite  and  selenite  are  also  transparent  to  ultra-violet  rays, 
but  these  crystalline  materials  are  rare  and  not  in  common  use.  However, 
a  moderate  thickness  of  ordinary  clear  glass,  sheets  of  clear  or  amber 
mica,  and  of  clear  or  colored  celluloid  or  gelatine  are  opaque  to  these 
dangerous  rays.  As  a  case  in  point,  it  is  well  known  that  the  mercury 
vapor  lamp,  when  made  with  a  quartz  tube,  is  an  exceedingly  dangerous 
light  to  the  eye,  being  a  prolific  source  of  ultra-violet  radiation,  so  that 
when  it  is  used  for  illumination,  it  is  always  carefully  enclosed  in  an 
outer  globe  of  glass.  When  the  mercury  vapor  lamp,  however,  is  made 
with  a  clear  glass  tube  it  is  a  harmless,  if  not  very  agreeable,  source  of 
light,  because  the  outer  tube  of  clear  glass  is  opaque  to  the  ultra-violet 
rays  that  are  generated  abundantly  within  it  by  the  highly  luminescent 
mercury  vapor. 

When  operating  with  a  source  of  light  that  is  known  to  be  rich  in 
ultra-violet  rays,  such  as  the  iron  arc  in  welding  operations,  it  is  not 
sufficient  to  guard  the  eyes  with  ordinary  spectacles  because  these  invisible 
rays  are  capable  of  reflection,  just  the  same  as  visible  light,  and  injury 
may  easily  ensue  from  slanting  reflections  reaching  the  eye  behind  the 
spectacle  lenses.  Goggles  that  fit  closely  around  the  eyes  are  the  only 
sure  protection  in  such  cases.  Also,  when  using  a  hand  shield  it  should 
be  held  close  against  the  face  and  not  several  inches  away  from  it. 

It  may  here  be  mentioned  that  the  invisible  ultra-violet  rays,  when  they 
are  not  masked  or  overpowered  by  intense  visible  light,  produce  the  curious 
visible  effect  termed  "fluorescence"  in  many  natural  and  artificial  com- 
pounds. That  is,  these  rays  cause  certain  compounds  to  shine  with  various 
bright  characteristic  colors,  when  by  visible  light  alone  they  may  appear 
pure  white  or  of  some  weak  neutral  tint.  Thus,  natural  willemite,  or  zinc 
silicate,  from  certain  localities  (which  may  also  le  made  artificially) 
shows  a  bright  green  color  under  the  light  from  a  disruptive  spark  between 
iron  terminals;  whereas  this  compound  is  white  or  nearly  so  by  visible 
light.  Also,  all  compounds  of  salicylic  acid,  such  as  the  sodium  salicylate 
tablets  which  may  be  bought  at  any  drug  store,  are  pure  white  when  seen 
by  visible  light,  but  show  a  beautiful  blue  fluorescence  under  ultra-violet 
rays.  Many  other  chemical  compounds  could  be  mentioned  which  possess 
this  curious  property,  but  the  above  substances  will  suffice  to  illustrate 
the  effect  of  fluorescence  produced  by  ultra-violet  rays,  and  by  which  these 
rays  may  be  thereby  detected.  It  must,  however,  be  noted  that  these 
substances  will  only  show  their  fluorescent  colors  very  faintly  when  viewed 
by  the  light  of  the  low-tension  iron  arc  used  in  welding,  because  the  intense 
visible  light  of  this  arc  will  overpower  the  weaker  effect  of  the  invisible 
ultra-violet  rays.  The  true  beauty  of  fluorescent  colors  can  only  be  seen 
under  a  high-tension  disruptive  discharge  between  iron  terminals,  the  visible 
light  in  this  case  being  weak  while  the  ultra-violet  rays  are  comparatively 
intense. 

Summarizing  the  effective  means  for  eye  protection  against  the  various 


ARC   WELDING  EQUIPMENT  27 

harmful  radiations  that  are  particularly  associated  with  welding  operations: 

(1)  The   intense    glare    and    flickering    of   the    visible    rays   should    be 
softened  and  toned  down  by  suitably  colored  glasses,  selected  by  an  expert 
and  having  a  depth  of  coloration  which  shows  the  clearest  definition  com- 
bined with  sufficient  obscuration  of  glare,  which  last  feature  can  be  best 
determined  by  the  individual  operator. 

(2)  When  infra-red  rays  are  present  to  a  dangerous  degree,  a  tested 
heat-absorbing  or  heat-reflecting  glass  should  be  employed,  either  in  com- 
bination with  a  suitable  dark  colored  glass,  when  glaring  visible  light  is 
present,  or  by  itself  in  cases  where   the  visible   rays  are  not   injuriously 
intense. 

(3)  In  guarding  the  eye  from  the  dangerous  ultra-violet  rays,  it  must 
be    carefully   noted    that    "pebble"    lenses    are    made    from    clear    quartz 
or  natural  rock  crystal,  and  this  material  being  transparent  to  these  rays 
offers  no  protection  against  their  harmful  features.     On  the  other  hand, 
ordinary  clear  glass  is  a  protection  against  these  rays  when  they  are  not 
very   intense,  but   dark-amber   or   dark-amber-grecn   glasses   are   absolutely 
protective.    Glasses  showing  blue  or  violet  tints  should  be  avoided,  excepting 
in  certain  combinations  wherein  they  may  be  used  to  obscure  othor  colors. 


UNIVERSITY  OF  CALIFORNIA 
EPARTMENT  OF  C,V,L   ENGINEER,,* 
BERKELEY,  CALIFORNIA 


CHAPTER   III 
DIFFERENT  MAKES  OF  ARC  WELDING  SETS 

In  showing  examples  of  different  makes  and  types  of  arc 
welding  sets,  only  enough  will  be  selected  to  cover  the  field  in 
a  general  way,  and  no  attempt  whatever  will  be  made  to  make 
the  list  complete. 

The  General  Electric  Co.,  Schenectady,  N.  Y.,  puts  out  the 


FIG.  22.— Oeneral  Electric   3-KW.,  1700-K.P.M.,  125-60-20- V.     Compound- 
wound  Balancer-Type  Arc  Welding  Set. 

constant  energy  metallic  electrode  set  shown  in  Fig.  22.  This, 
however,  is  but  one  type  of  its  machines  as  this  company  makes 
a  varied  line  covering  all  needs  for  welding  work.  Two  of  their 
commonly  used,  up-to-date  sets  are  illustrated  in  Figs.  131  and 
132,  Chapter  VIII. 

This  particular  machine  combines  high  arc  efficiency  and 
light  weight.  The  balancer  set  is  of  the  well-known  G-E  standard 
"MCC"  construction.  It  is  built  for  operation  on  125-v.,  d.c. 
supply  circuits,  which  may  be  grounded  on  the  positive  side  only, 
and  is  rated  "MCC"  3  kw.,  1,700  revolution,  125/60/20  v.,  com- 

28 


DIFFERENT   MAKES  OF  ARC  WELDING  SETS  29 

pound-wound,  150  amperes,  RC-27-A  frames,  the  two  armatures 
being  mounted  on  one  shaft  and  connected  in  series  across  the 
125-v.  supply  circuit,  one  welding  circuit  terminal  being  taken 
from  the  connection  between  the  two  armatures  and  the  other 
from  the  positive  line.  By  this  means  each  machine  supplies 
part  of  the  welding  current  and,  consequently,  its  size  and  weight 
is  minimized.  The  design  of  the  fields  and  their  connections 
is  such  that  the  set  delivers  the  voltage  required  directly  to  the 
arc  without  the  use  of  resistors  or  other  energy-consuming 
devices.  The  bearings  are  waste  packed:  this  type  of  bearing 


FIG.  23. — Welding  Control  Panel  for  Balancer  Set. 

being  desirable  in  a  set  which  is  to  be  made  portable  either  for 
handling  by  a  crane  or  for  mounting  on  a  truck. 

The  welding  control  panel  for  the  balancer  set  is  shown  in 
Fig.  23.  This  panel  consists  of  a  slate  base,  24-in.  square,  which 
is  mounted  on  24-in.  pipe  supports  for  portable  work  and  on 
64-in,  pipe  supports  for  stationary  work. 

The  entire  set  consists  of  one  ammeter,  one  voltmeter,  one 
dial  switch,  two  field  rheostats  (motor  and  generator)  one  start- 
ing equipment  witlf  fuse,  one  reactor  mounted  on  the  pipe  frame 
work  of  panel.  The  ammeter  and  voltmeter  are  enclosed  in  a 
common  case.  The  ammeter  indicates  current  in  the  welding 


30 


ELECTRIC   WELDING 


circuit  and  the  voltmeter  is  so  connected  that  by  means  of  a 
double-throw  switch,  either  the  supply  line  voltage  or  the  welding 
line  voltage  can  be  read. 

The  dial  switch  is  connected  to  taps  in  the  series  field  of 


-t-itr 

La 

185  V.  D.  C. 
Reactor 


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Field  Armature 


Co  mm.  Generator 
Field       Armature 


FIG.  24. — Balancer    and    Control    Panel    Connections    for   General    Electric 
Constant-Energy  Constant-Arc  Set. 

the  generator,  the  field  being  connected  to  oppose  the  main  field. 
This  feature  provides  the  current  control  by  which  six  steps 
are  obtained  of  the  approximate  values  of  50, 70, 90, 110, 130  and 
150  amp.,  which  enables  the  operator  to  cover  a  very  wide  range. 


DIFFERENT   MAKES   OF   ARC   WELDING   SETS 


31 


In  addition,  if  intermediate  current  values  are  required,  they  can 
be  obtained  by  means  of  the  generator  field  rheostat. 

A  small  reactor  is  used  to  steady  the  arc  and  current  both 
on  starting  and  during  the  period  of  welding. 

Arc  welding  is  usually  done  on  metal  which  is  grounded  and 
this  is  especially  unavoidable  in  ship  work,  where  the  ship  struc- 
ture is  always  well  grounded.  Since  successful  operation  requires 
that  the  positive  terminal  be  connected  to  the  work  the  supply 
circuit  should  be  safely  grounded  on  the  positive  side. 

Where  a  125-v.,  d.c.  supply  system  is  not  available,  standard 


Thickness 

FIG.  25. — Carbon   Electrode   Cutting   Speeds  for  Different   Thicknesses 

of  Plate. 

"MIC"  or  "MCC"  sets  are  furnished  to  supply  power  at  125  v., 
the  motor  being  either  3-phase,  60-cycle,  220,  440  or  550  v.,  or 
d.c,,  230  or  550  v.,  and  in  three  capacities,  5J  kw.,  7  kw.,  and 
15  kw.  With  each  motor  generator  set  there  is  supplied  a  panel 
containing  generator  field  rheostat  and  motor  starter,  which  may 
be  mounted  beside  the  balancer  panel.  A  diagram  showing  the 
balancer  and  control  panel  is  shown  in  Fig.  24. 

The  constant  energy  arc-welding  equipment  supplies,  to  the 
arc,  practically  constant  energy  throughout  the  welding  range 
for  metallic  electrode  welding  only.  If  the  arc  is  lengthened 
slightly  the  voltage  increases  and  the  current  decreases,  the  total 


32 


ELECTRIC   WELDING 


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DIFFERENT   MAKES  OF   ARC   WELDING  SETS 


33 


energy  being  practically  constant.  As  the  voltage  required  by 
the  arc  varies,  the  generator  readjusts  itself  to  this  condition 
and  automatically  supplies  the  required  voltage;  the  remainder 
being  utilized  by  the  motor  end  of  the  set.  The  interchange 
of  voltage  between  the  motor  and  generator  is  practically  in- 
stantaneous, no  perceptible  lag  occurs.  This  feature  is  valuable 
when  metal  drops  from  the  electrode  and  causes  an  instantaneous 
increase  in  current.  The  commutation  is  sparkless  and  the  weld- 


Pie.  26.— Wilson  Two-Arc,  300  Amp.,  "Plastic  Arc"  Welding  Set. 

ing  circuit  may  be  short-circuited  without  injury  to  the  machine. 

In  connection  with  welding  with  an  outfit  of  this  kind,  the 
practical  man  and  student  will  find  Table  III  of  considerable 
interest.  For  sheet  steel  cutting  using  the  carbon  arc,  the 
chart  Fig.  25  is  given. 

The  Wilson  Outfit.— The  Wilson  "plastic  arc"  process  and 
apparatus  was  first  developed  in  railroad  work  by  the  Wilson 
Welder  and  Metals  Co.,  New  York,  in  order  to  enable  the 
welder  to  control  the  heat  used.  By  this  system  it  is  claimed 


34 


ELECTRIC  WELDING 


that  any  number  of  operators  can  work  from  one  large  machine 
without  one  welder  interfering  in  any  way  with  the  work  of 
another.  Each  operator  can  have  properly  controlled  heat  and 
a  steady  arc  at  the  point  of  application.  This  system  was 


Fie.  27.— Welding  and  Cutting  Panel  for  Wilson  Set. 

largely  used  in  the  repair  of  the  damaged  engines  on  the  Ger- 
man ships  which  were  seized  by  us.  By  regulating  the  heat 
it  is  claimed  that  any  metal  can  be  welded  without  preheating. 
A  two-arc  set  is  shown  in  Fig.  26  and  a  close-up  of  a  control 
panel  in  Fig.  27. 


DIFFERENT  MAKES  OF  ARC  WELDING  SETS  35 

This  outfit  consists  essentially  of  a  constant  voltage 
generator  driven  by  any  constant-speed  motor,  all  mounted 
on  a  common  bedplate.  The  regulation  of  the  welding  current 
is  maintained  by  means  of  a  series  carbon  pile  acting  as  a 
series  resistance  of  varying  quantity  under  the  action  of  increas- 
ing or  decreasing  mechanical  pressure.  This  pressure  is 
produced  by  means  of  a  series  solenoid  operating  mechanically 
on  a  lever  and  spring  system  which  varies  the  pressure  on 
the  carbon  pile  inversely  as  the  current  in  the  main  circuit. 
This  establishes  a  constant  current  balance  at  any  predeter- 
mined adjustment  between  a  maximum  and  minimum  range 
designed  for.  The  change  in  adjustment  is  controlled  by  the 
operator  at  the  point  of  work  by  means  of  a  small  pilot  motor 
which  shifts  the  lever  center  of  the  pressure  mechanism, 
thereby  raising  or  lowering  the  operating  current.  This  system 
maintains  a  constant  predetermined  current  at  the  arc  regard- 
less of  the  arc  length.  The  operation  of  the  mechanism  is 
positive  and  quick  acting.  A  special  series  choke-coil  is 
mounted  on  the  control  panel  for  use  as  a  cutting  resistance. 

" Plastic  Arc"  Dynamotor  Unit.— The  "plastic  arc"  weld- 
ing unit  illustrated  in  Fig.  28,  while  embodying  the  same 
fundamental  principles  as  the  foregoing,  is  a  later  model.  This 
set  is  composed  of  a  dynamotor  and  current  control  panel. 
The  generator  is  flat-compound  wound,  and  maintains  the 
normal  voltage  of  35  on  either  no  load  or  full  load. 

The  control  panel  has  been  designed  to  provide  a  constant- 
current  controlling  panel,  small  in  size,  of  light  weight, 'simple 
in  operation  and  high  in  efficiency.  The  panel  is  of  slate, 
20  in.X27  in.,  and  on  it  are  mounted  a  small  carbon  pile,  a 
compression  spring,  and  a  solenoid  working  in  opposition  to 
the  spring.  The  solenoid  is  in  series  with  the  arc  so  that  any 
variation  in  current  will  cause  the  solenoid  to  vary  the  pressure 
on  the  carbon  pile,  thereby  keeping  the  current  constant  at  the 
value  it  is  adjusted  for. 

Three  switches  on  the  panel  provide  an  easy  means  of  cur- 
rent adjustment  between  25  and  175  amperes.  The  arrange- 
ment of  the  welding  circuit  is  such  that  25  amperes  always 
flow  through  the  solenoid  when  the  main  switch  is  closed, 
whether  the  welding  current  is  at  the  minimum  of  25  amperes 
or  the  maximum  of  175  amperes.  The  balance  of  the  welding 


36 


ELECTRIC  WELDING 


current  is  taken  care  of  in  by-pass  resistances  shunted  around 
the  solenoid. 

This  outfit  can  be  furnished  as  a  dynamotor  unit,  with 
standard  motor  characteristics  as  follows :  110  volts  or  220  volts 
direct  current,  or  220  or  440  volts,  60  cycle,  2  or  3  phase, 
alternating  current;  also  as  a  gasoline-driven  unit,  or  it  can 


FIG.  28. — "  Plastic- Arc  "  Dynamotor  Welding  Unit. 

be  furnished  without  a  motor,  to  be  belt  driven.  The  normal 
generator  speed  is  1800  r.p.m.  The  net  weight  is  800  Ib.  with 
direct-current  motor,  807  Ib.  with  alternating-current  motor, 
1200  Ib.  with  gasoline  engine,  and  550  Ib.  as  a  belted  outfit 
without  motor.  The  sets  can  be  mounted  on  a  truck  for  easy 
portability  if  desired. 

The  Lincoln  Outfit. — The  portable  arc-welding  outfit  illus- 


DIFFERENT   MAKES  OF  ARC   WELDING  SETS 


37 


trated  in  Fig.  29  is  the  product  of  the  Lincoln  Electric  Co., 
Cleveland,  Ohio.  The  outfit  is  intended  for  operation  where 
electric  current  is  not  available  and  consists  of  a  150-amp. 
arc-welding  generator  direct  connected  to  a  Winton  gasoline 
engine.  An  interesting  feature  of  the  machine  is  the  method 
used  to  insure  a  steady  arc  and  a  constant  and  controllable 
heat.  A  compound-wound  generator  is  used,  the  series  wind- 


FIG.  29. — Lincoln  Self-Contained  Portable  Set. 

ings  of  which  are  connected  to  oppose  the  shunt  field,  the  two 
windings  being  so  proportioned  that  the  voltage  increases  in 
the  same  ratio  that  the  current  increases,  thus  limiting  the 
short-circuit  current.  Another  important  effect  of  this  is  that 
the  horsepower,  and  therefore  the  heat  developed  for  a  given 
getting  of  the  regulator  switch  shown  on  the  control  board 
above  the  generator  remains  practically  constant.  It  is  claimed 
that  this  method  of  control  gives  considerably  more  work 


38 


ELECTRIC  WELDING 


on  a  given  amount  of  electricity  than  where  the  machines  use 
the  ballast  resistance.  Additional  arc  stability  is  insured  by 
the  stabilizer  at  the  right  of  the  illustration,  this  being  a  highly 
inductive  low-resistance  coil  connected  in  the  welding  circuit 
and  serving  to  correct  momentary  fluctuations  of  current. 

Westinghouse  Single- Operator  Electric  Welding  Outfit. — 
The  single-operator  electric  arc-welding  equipment  shown  in 
Fig.  30  is  manufactured  by  the  Westinghouse  Electric  and 
Manufacturing  Co.,  East  Pittsburgh,  Pa.  The  generator 


FIG.  30. — Westinghouse  Single-Operator  Portable  Outfit. 

operates  at  arc  voltage  and  no  resistance  is  used  in  circuit 
with  the  arc.  The  generator  is  designed  to  inherently  stabilize 
the  arc,  thereby  avoiding  the  use  of  relays,  solenoid  control- 
resistors,  etc. 

The  generator  has  a  rated  capacity  of  175  amp.  and  is 
provided  with  commutating  poles  and  a  long  commutator, 
which  enable  it  to  carry  the  momentary  overload  at  the  instant 
of  striking  an  arc  without  special  overload  device.  Close  adjust- 
ment of  current  may  be  easily  and  quickly  made,  and,  once 


DIFFERENT   MAKES  OF  ARC  WELDING  SETS 


39 


made,  the  amount  of  current  at  the  weld  will  remain  fixed 
within  close  limits  until  changed  by  the  operator.  There  are 
twenty-one  steps  provided  which  give  a  current  regulation  of 
less  than  9  amp.  per  step  and  make  it  much  easier  for  a  welder 
to  do  vertical  or  overhead  work. 

The  generator  is  mounted  on  a  common  shaft  and  bedplate 
with  the  motor.  A  pedestal  bearing  is  supplied  on  the  com- 
mutator end  and  carries  a  bracket  for  supporting  the  exciter 
which  is  coupled  to  the  common  shaft.  Either  d.c.  or  a.c. 
motors  can  be  supplied.  Where  an  a.c.  motor  is  used  leads 


FIG.  31.— U.  S.  L.  Portable,  A-C.  Motor-Generator  Set. 

are  brought  outside  the  motor  frame  for  connecting  either 
220-  or  440-v.  circuits.  An  electrician  can  change  these  con- 
nections in  a  few  minutes'  time.  This  feature  is  desirable  on 
portable  outfits  which  may  be  moved  from  one  shop  to  another 
having  a  supply  circuit  of  different  voltages.  For  portable 
service,  the  motor-generator  set  with  the  control  panel  is 
mounted  on  a  fabricated  steel  truck,  equipped  with  roller- 
bearing  wheels.  The  generator  is  compound-wound,  flat  com- 
pounded, that  is,  it  delivers  60  v.  at  no-load  and  also  at  full- 
load. 


40  ELECTRIC  WELDING 

The  U.  S.  Light  and  Heat  Co.'s  Outfit.— The  portable  outfit, 
Fig.  31,  is  made  by  the  U.  S.  Light  and  Heat  Corp.,  Niagara 
Falls,  N.  Y.  It  is  28  in.  wide,  55  in.  high,  54  in.  long,  and 
will  pass  through  the  narrow  aisle  of  a  crowded  machine  shop. 
It  weighs  1,530  Ib.  complete.  In  case  a  d.c.  converter  is  used, 
the  weight  is  about  125  Ib.  less.  Curtains  are  provided  to  keep 
out  dirt.  A  substantial  cable  reel  is  provided  carrying  two 
50-ft.  lengths  of  flexible  cable  for  carrying  the  current  to  the 
arc.  The  reel  is  controlled  by  a  spring  which  prevents  the 
paying  out  of  more  cable  than  the  welder  needs.  The  outfit 
is  made  in  several  models  to  use  4  kw.,  110-220-440-550  v., 
2  and  3  phase,  25  and  60  cycle. 

The  Arc  Welding  Machine  Co.'s  Constant-Current  Closed- 
Circuit  System. — The  constant-current  closed-circuit  arc  welding 


fefcrf 


FIG.  31A.— The  Are  Welding  Machine  Co.'s  Outfit. 

system  developed  by  the  Arc  Welding.  Machine  Co.,  New  York, 
permits  the  use  of  an  inherently  regulating  generator  with  more 
than  one  arc  on  a  single  circuit.  This  system  is  claimed  to  be 
especially  adapted  to  production  welding  applications. 

The  method  has  all  the  advantages  of  series  distribution, 
namely,  the  size  of  wire  is  uniform  throughout  the  system  and 
carries  a  uniform  current,  independent  of  the  length  of  the 
circuit  as  well  as  of  the  number  of  operators.  The  circuit  is 
simply  a  single  wire  of  sufficient  cross-section  to  carry  the 
current  for  one  arc,  run  from  the  generator  to  the  nearest  arc, 
from  there  to  the  next,  and  so  on  back  to  the  generator. 
Wherever  it  is  desired  to  do  welding,  a  switch  is  inserted  in 
the  line,  and  a  special  arc  controller  provided  with  suitable 
connections  is  plugged  in  across  the  switch  whenever  work 


DIFFERENT   MAKES  OF  ARC  WELDING  SETS  41 

is  to  be  done.  These  controllers  may  be  made  portable  or 
permanently  mounted  at  the  welding  station. 

The  set  shown  in  Fig.  31A  consists  of  two  units:  The 
generator  proper  which  furnishes  the  energy  for  welding,  and 
the  regulator  which  automatically  maintains  the  current  at  a 
constant  value.  The  regulator  is  excited  from  a  separate 
source,  and,  by  varying  its  excitation  with  an  ordinary  field 
rheostat,  the  main  welding  current  may  be  set  at  any  value 
within  the  range  of  the  machine  that  is  desired,  and  once  set 
it  will  automatically  maintain  that  value. 

Each  arc  that  is  operated  on  the  system  is  equipped  with 
an  automatic  controller  which  serves  two  essential  purposes: 

1 — It  maintains  at  all  times  the  continuity  of  the  circuit, 
so  that  one  arc  cannot  interfere  with  any  of  the 
others  when  it  comes  on,  or  goes  out  of,  the  circuit. 

2 — It  controls  automatically  the  heat  which  can  be  put 
into  the  metal  of  the  weld. 

The  current  through  the  arc,  together  with  the  size  of  the 
electrode,  determines  the  flow  of  metal  from  the  electrode,  and 
this  current  is  adjusted  by  shunting  a  portion  of  the  main 
current  around  the  arc.  The  regulation  characteristic  of  the 
arc  may  be  adjusted  by  a  series  parallel  resistance,  which  is 
one  of  the  special  features.  When  doing  work  on  very  thin, 
•light  metals,  especially  where  the  weld  must  be  tight,  it  is 
necessary  that  fusion  take  place  from  the  first  instant  the 
arc  is  struck.  If  the  heat  of  the  arc  is  exactly  right  for 
continuous  operation,  it  will  not  be  enough  at  the  first  instant, 
and  if  it  is  sufficient  to  produce  fusion  at  once,  then  it  will 
be  too  much  a  few  seconds  later.  On  this  account  a  special 
type  of  controller  is  used  for  such  work  which  provides  for 
automatic  reduction  at  a  definite  time  after  the  arc  is  actually 
started,  and  continuing  for  a  definite  time  and  at  a  definite 
rate.  Both  periods  of  time  and  the  rate  and  magnitude  of 
the  current  change  are  adjustable. 

For  a  given  flow  of  metal  through  the  arc  the  temperature 
of  the  metal  is  determined  by  the  length  of  the  arc,  that  is, 
by  the  voltage.  With  this  controller,  the  length  of  the  arc 
limited  by  the  voltage  is  adjusted  to  suit  the  work  and  the 
operator,  and  if  exceeded,  the  arc  is  short-circuited  automat- 


42 


ELECTRIC  WELDING 


ically   and  remains  short-circuited  until  the  welder  is   ready 
to  begin  again. 

Provision  is  also  made  for  stopping  the  arc  at  will  without 
lengthening  it.  Therefore  it  is  claimed  that  with  this  system 
it  is  impossible  to  draw  a  long  arc  and  burn  the  metal.  The 
arc  is  not  broken  when  the  welding  operation  is  stopped,  but 
is  killed  by  a  short-circuit  which  is  placed  across  it. 


FIG.  32. — Zeus  Arc- Welding  Outfit. 

Stopping  an  arc  by  short-circuiting  and  limiting  the  heat 
production  in  the  same  way  is  a  patented  feature. 

"Zeus"  Arc- Welding  Outfit.— The  "Zeus"  arc-welding  out- 
fit shown  in  Fig.  32  is  a  product  of  the  Gibb  Instrument  Co., 
1644  Woodward  Ave.,  Detroit,  Mich.  In  this  device  the  motor- 
generator  customarily  used  has  been  supplanted  by  a  trans- 


DIFFERENT   MAKES  OF  ARC   WELDING  SETS  43 

former  with  no  moving  parts.  The  outfit  is  built  on  a  unit 
system,  which  allows  the  installation  of  a  small  outfit,  and 
if  the  work  becomes  heavier  a  duplicate  set  may  be  connected 
in  parallel.  One  of  the  features  of  the  machine  is  the  arrange- 
ment for  regulation.  It  is  not  necessary  to  change  any  con- 
nection for  this  purpose,  as  a  wheel  connected  with  a  secondary 
and  placed  on  the  top  of  the  case  raises  and  lowers  this 
secondary,  and  provides  the  regulation  of  current  necessary  for 


FIG.  33. — Arcwell  Outfit  for  Alternating  Current. 

different  sizes  of  electrodes.  The  inherent  reactance  of  the 
outfit  automatically  stabilizes  the  arc  for  different  arc  lengths. 
The  Arcwell  Outfit. — The  Arcwell  Corporation,  New  York, 
has  on  the  market  an  electric  welding  apparatus  built  for 
operation  on  alternating  current  of  any  specified  voltage  or 
frequency.  It  is  shown  in  Fig.  33.  It  differs  from  the  com- 
pany's standard  outfit  in  that  it  is  being  put  out  expressly 
for  the  use  of  smaller  machine  shops  and  garages,  its  capacity 
not  being  sufficient  to  take  care  of  heavy  work  on  a  basis  of 


44  ELECTRIC  WELDING 

speed.  It  will  do  any  work  that  can  be  done  by  the  larger 
machines,  but  the  work  cannot  be  performed  as  rapidly,  the 
machine  being  intended  especially  for  use  by  concerns  who 
have  only  occasional  welding  jobs  to  perform.  The  machine 
weighs  approximately  200  Ib.  and,  being  mounted  on  casters, 
it  can  be  moved  from  one  job  to  another. 

Alternating-Current  Arc- Welding  Apparatus. — The  Electric 
Arc  Cutting  and  Welding  Co.,  Newark,  N.  J.,  is  now  marketing 
the  alternating-current  arc-welding  outfit  shown  in  Fig.  34. 

This  illustration  shows  the  entire  apparatus  for  use  on  a 


FIG.  34. — Apparatus  Made  by  the  Electric  Arc  Cutting  and  Welding  Co. 

single-phase  circuit,  the  current  being  brought  in  through  the 
wires  seen  protruding  at  the  lower  left  corner. 

The  device  consists  principally  of  a  transformer  with  no 
moving  parts  and  is  claimed  to  last  indefinitely.  In  this  ap- 
paratus, instead  of  holding  either  current  or  voltage  constant 
as  with  direct-current  sets,  the  wattage,  or  the  product  of 
voltage  and  current,  is  held  constant.  The  alternating-current 
set  holds  the  arc  wattage  without  moving  parts ;  hence  the  heat 
is  substantially  constant  for  any  given  setting,  and  it  is  claimed 
that  as  soon  as  any  person  becomes  accustomed  to  the  sound 
and  sight  of  the  arc  and  can  deposit  the  molten  metal  where 
he  desires  it  is  impossible  to  burn  the  metal  from  too  much 
heat  or  make  cold-shut  welds  from  too  little  heat.  The  amount 


DIFFERENT   MAKES  OF  ARC   WELDING   SETS  45 

of  heat  generated  is  controlled  by  means  of  an  adjusting  handle 
on  the  transformer  together  with  taps  arranged  on  a  plugging 
board.  It  is  stated  that  the  kilowatt-hours  required  to  deposit 
a  pound  of  mild  steel  with  this  machine  varies  from  1£  to  2£. 
Their  largest  set  is  a  60-cycle  type  weighing  about  200  lb., 
which  places  it  in  the  portable  class.  The  set  can  be  furnished 
for  any  a.c.  power  supply,  but  it  is  not  advisable  to  use  a 
greater  voltage  than  650  on  the  primary.  The  set  can  also  be 
made  single  phase,  two  phase  three  wire,  two  phase  four  wire, 


FIG.  35. — General  Electric  Lead-Burning  Outfit. 

to  operate  across  the  outside  wires  of  the  two-phase  system 
or  from  a  three-phase  power  supply.  Polyphase  sets  are  about 
30  per  cent -heavier  than  the  single-phase  sets.  In  the  two- 
phase  machine  balanced  current  can  be  drawn  from  each  of 
the  two  phases  by  placing  the  sets  across  the  outside  wires. 
This  is  advocated,  as  it  provides  for  leading  current  on  one 
phase  which  brings  up  the  total  power  factor  of  the  system  and  a 
better  power  rate  can  be  obtained.  In  polyphase  circuits  where 
more  than  one  set  is  used  single-phase  sets  can  be  distributed 
among  the  several  phases. 

The  outfit  can  be  made  especially  for  welding  and  for  cut- 


46  ELECTRIC  WELDING 

ting  or  for  combination  welding  and  cutting  and  can  make 
use  of  bare  wire,  slag-covered,  gaseous  fluxed  or  carbon  elec- 
trodes. An  operator's  mask  and  the  electrode  holder  used 
may  be  seen  on  top  of  the  apparatus. 

General  Electric  Lead-Burning  Transformer. — This  lead- 
burning  transformer,  Fig.  35,  a  product  of  the  General  Electric 
Co.,  Schenectady,  N.  Y.,  can  be  used  for  lead  burning,  soldering 
electric  terminals,  splicing  wires  and  tinsmith  jobs,  and  even 
brazing  can  be  done  by  placing  the  work  between  a  blunt 
carbon  point  and  a  piece  of  cast  iron.  The  transformer  is 
designed  to  be  connected  to  the  ordinary  110-v.,  a.c.  lighting 
circuit.  Heavy  rubber-covered  terminal  leads  are  used  to 
convey  the  low-voltage,  heat-producing  current  to  the  work, 
one  terminal  ending  in  a  clip  for  fastening  to  some  convenient 
portion  of  the  work  while  the  other  terminal  has  a  carbon 
holder  arranged  with  an  insulated  handle.  When  the  welding 
carbon  is  brought  into  contact  with  the  work  the  pointed  end 
becomes  intensely  hot  and  melts  the  metal  over  a  restricted 
area.  It  should  be  noted  that  no  arc  is  drawn,  the  end  of 
the  carbon  point  being  heated  to  such  a  temperature  that,  the 
metal  in  the  vicinity  is  melted.  The  device  uses  about  800 
watts  while  in  actual  use,  the  consumption  dropping  to  4J 
watts  when  the  point  is  removed  from  the  work.  It  is  stated 
that  the  device  is  very  convenient  in  plumbing,  roofing  and 
tank-building  jobs,  as  well  as  other  such  work. 


CHAPTER  IV 
TRAINING  ARC  WELDERS 

Writing  on  the  training  of  arc  welders,  in  the  American 
Machinist,  April  15,  1920,  0.  H.  Eschholz,  research  engineer 
of  the  Westinghouse  Electric  and  Mfg.  Co.,  Pittsburgh,  says : 

Many  industrial  engineers  are  now  facing  the  problem  of 
developing  competent  welders.  This  situation  is  attributed  to 
the  rapid  growth  of  the  metallic  electrode  arc-welding  field 
as  the  result  of  the  successful  application  of  the  process  to 
war  emergencies.  The  operator's  ability,  it  is  now  generally 
conceded,  is  the  most  important  factor  in  the  production  of 
satisfactory  welds.  To  facilitate  the  acquirement  of  the  neces- 
sary skill  and  knowledge,  the  following  training  course  con- 
siders in  their  proper  sequence  the  fundamental  characteristics 
and  operations  of  the  bare  metallic  electrode  arc-welding 
process. 

It  is  well  known  that  the  iron  arc  emits  a  large  quantity 
of  ultra-violet  radiation.  Protection  from  the  direct  rays  is 
usually  afforded  by  the  use  of  hand  shields.  Many  uncom- 
fortable burns,  however,  have  been  traced  to  reflected  radiation. 
To  secure  adequate  protection  from  both  direct  and  reflected 
light  it  is  necessary  for  the  welder  to  use  a  fiber  hood  equipped 
with  suitable  glasses.  Paper  No.  325  of  the  Bureau  of 
Standards  on  "  Spectroradiometric  Investigation  of  the  Trans- 
mission of  Various  Substances"  concludes  that  the  use  of  amber 
and  blue  glasses  will  absorb  most  of  the  ultra-violet  as  well 
as  infra-red  radiation.  To  protect  the  operator  from  incan- 
descent particles  expelled  by  the  arc,  closely  woven  clothing, 
a  leather  apron,  gauntlets  and  bellows-tongued  shoes  should 
be  worn. 

If  the  welding  booth  is  occupied  by  more  than  one  welder, 
it  will  be  found  desirable  to  equip  each  operator  with  amber 
or  green-colored  goggles  to  reduce  the  intensity  of  accidental 

47 


48  ELECTRIC  WELDING 

" flashes"  from  adjacent  arcs  after  the  welder  has  removed 
his  hood. 

The  Welding  Booth. — The  difficulty  of  maintaining  an  arc 
is  greatly  increased  by  the  presence  of  strong  air  currents.  To 
avoid  the  resulting  arc  instability,  it  is  desirable  to  inclose 
the  welder  on  at  least  three  sides,  with,  however,  sufficient 
ventilation  provided  so  that  the  booth  will  remain  clear  from 
fumes.  By  painting  the  walls  a  dull  or  matte  black  the  amount 
of  arc  radiant  energy  reflected  is  reduced. 

The  electrode  supply  and  means  of  current  control  should 
be  accessible  to  the  operator.  When  using  bare  electrodes  the 
positive  lead  should  be  firmly  connected  to  a  heavy  steel  or 
cast-iron  plate,  mounted  about  20  in.  above  the  floor.  This 
plate  serves  as  the  welding  table. 

Welding  Systems. — Many  commercial  sets  compel  the 
operator  to  hold  a  short  arc.  This  characteristic  favors  the 
production  of  good  welds  but  increases  the  difficulty  of  main- 
taining the  arc.  By  increasing  the  stability  of  the  arc  through 
the  use  either  of  covered  electrodes,  series  inductances  or  in- 
creased circuit  voltage  and  series  resistance,  the  acquisition  of 
the  purely  manipulative  skill  may  be  accelerated. 

The  Electrode  Holder. — The  electrode  holder  should  remain 
cool  in  service,  shield  the  welding  hand  from  the  arc,  facilitate 
the  attachment  and  release  of  electrodes,  while  its  weight, 
balance  and  the  drag  of  the  attached  cable  should  not  produce 
undue  fatigue.  A  supply  of  different  types  of  covered  and 
bare  electrodes  should  be  carried  by  the  welding  school  so 
that  the  operator  may  become  familiar  with  their  operating 
and  fusing  characteristics. 

The  degree  of  supervision  the  welder  is  to  receive  de- 
termines the  source  of  operator  material.  If  the  welding  opera- 
tions are  to  be  supervised  thoroughly  and  the  function  of  the 
welder  is  simply  that  of  uniting  suitably  prepared  surfaces, 
the  candidate  may  be  selected  from  the  type  of  men  who  usually 
become  proficient  in  skilled  occupations.  If,  however,  the 
responsibility  of  the  entire  welding  procedure  rests  upon  the 
operator,  he  should  be  drawn  from  members  of  such  metal 
trades  as  machinist,  boilermaker,  blacksmith,  oxy-acetylene 
welder,  etc.  Some  employers  find  it  expedient  to  use  simple 
eve  and  muscular  co-ordination  tests  to  determine  the  candi- 


TRAINING  ARC   WELDERS 


49 


date's  ability  to  detect  the  colors  encountered  in  welding  and 
to  develop  an  automatic  control  of  the  arc. 

With  adequate  equipment  provided,  the  operator  may  be 
instructed  in  the  following  subjects: 

1.  Manipulation  of  the  arc. 

2.  Characteristics  of  the  arc. 

3.  Characteristics  of  fusion. 

4.  Thermal  characteristics. 

5.  Welding  procedure. 

6.  Inspection. 

Arc  Manipulation. — A  sitting  posture  which  aids  in  the 
control  of  the  arc  is  shown  in  Fig.  36.    It  should  be  noted  that 


FIG.  36. — Correct  Welding  Posture  and  Equipment. 

by  resting  the  left  elbow  on  the  left  knee  the  communication 
of  body  movements  to  the  welding  hand  is  minimized,  while  by 
supporting  the  electrode  holder  with  both  hands  the  arc  may 
be  readily  directed.  During  the  first  attempts  to  secure  arc 
control  covered  electrodes  may  be  used,  as  these  greatly  increase 
arc  stability,  permitting  the  welder  to  observe  arc  characteris- 


50  ELECTRIC  1YELDING 

tics  readily.  It  is  suggested  that  throughout  the  training  period 
the  instructor  give  frequent  demonstrations  of  the  welding 
operations  as  well  as  occasionally  guide  the  apprentice's  weld- 
ing arm. 

Arc  Formation. — With  the  welding  current  adjusted  to  100 
amp.  and  a  5/S2-ui.  covered  electrode  in  the  holder,  the  operator 
assumes  the  posture  shown  and  lowers  the  electrode  until  con- 
tact is  made  with  a  mild-steel  plate  on  the  welding  table, 
whereupon  the  electrode  is  withdrawn,  forming  an  arc.  If  an 
insulating  film  covers  either  electrode  surface  or  the  current 
adjustment  is  too  low,  no  arc  will  be  drawn.  With  the  arc 
obtained  the  operator  should  note  the  following  characteristics 
of  arc  manipulation. 

Fusion  of  Electrodes. — The  fusion  of  electrodes  is  frequently 
called  "sticking"  or  " freezing. "  It  is  the  first  difficulty 
encountered  and  is  caused  either  by  the  use  of  an  excessive 
welding  current  or  by  holding  the  electrodes  in  contact  too 
long  before  drawing  the  arc.  This  fusing  tendency  is  always 
present  because  the  welding  operation  requires  a  current  den- 
sity high  enough  to  melt  the  wire  electrode  at  the  arc  terminal. 
When  such  fusion  occurs  the  operator  commits  the  natural 
error  of  attempting  to  pull  the  movable  electrode  from  the 
plate.  If  he  succeeds  in  separating  the  electrodes,  the  momen- 
tum acquired,  unless  he  is  very  skillful,  is  sufficient  to  carry 
the  electrode  beyond  a  stable  arc  length.  If,  however,  the  wrist 
of  the  welding  hand  is  turned  sharply  to  the  right  or  left, 
describing  the  arc  of  a  circle  having  its  center  at  the  electrode 
end,  the  fused  section  is  sheared  and  a  large  movement  of  the 
electrode  holder  produces  an  easily  controllable  separation  of 
the  arc  terminals. 

Maintenance  of  Arc. — After  forming  the  arc  the  chief  con- 
cern of  the  welder  should  be  to  maintain  it  until  most  of  the 
electrode  metal  has  been  deposited.  If  the  movable  electrode 
were  held  rigidly,  the  arc  would  gradually  lengthen  as  the 
electrode  end  melted  off  until  the  arc  length  had  increased 
sufficiently  to  become  unstable  and  interrupt  the  flow  of  cur- 
rent. To  maintain  a  constant  stable  arc  length  it  is  necessary 
for  the  operator  to  advance  the  wire  electrode  toward  the  plate 
at  a  rate  equal  to  that  at  which  the  metal  is  being  deposited. 
For  the  novice  this  will  prove  quite  difficult.  However,  if  the 


TRAINING   ARC   WELDERS  51 

initial  attempts  are  made  with  covered  electrodes,  which  per-" 
mit  greater  arc-length  variations  than  bare  electrodes,  the 
proper  degree  of  skill  is  soon  acquired. 

When  the  operator  succeeds  in  maintaining  a  short  arc 
length  for  some  time,  the  covered  electrode  should  be  replaced 
by  a  5/32-in-  diameter  bare  electrode,  the  welding  current  in- 
creased to  150  amp.  or  175  amp.  and  either  reactance  included 
in  the  circuit  or  the  voltage  of  the  welding  set  increased.  With 
increase  in  manipulative  skill  the  reactance  coil  may  be  short- 
circuited  or  the  supply  voltage  reduced  to  normal  and  practice 
continued  under  commercial  circuit  and  electrode  conditions. 

Further  instruction  should  not  be  given  until  the  candidate 
is  able  to  maintain  a  short  arc  during  the  entire  period  required 
to  deposit  the  metal  from  a  bare  electrode  14  in.  long,  5/32  in. 
in  diameter,  on  a  clean  plate  j  in.  in  thickness  when  using 
a  welding  current  of  150  amp.  The  arc  voltage  may  be  used 
as  a  measure  of  the  arc  length.  The  average  arc  voltage 
during  the  test  should  be  less  than  twenty-five,  as  this 
corresponds  to  a  length  of  approximately  J  in.  Some  operators 
meet  this  test  in  the  first  hour  of  their  training,  others  require 
two  or  three  days'  practice.  If  arc-length  control  is  not 
obtained  within  the  latter  period,  the  instructor  may  safely 
conclude  that  the  apprentice  is  physically  unfitted  for  the  occu- 
pation of  arc  welding.  If  the  test  is  satisfactory,  training 
should  be  continued,  using  bare  electrodes  but  with  such 
stabilizing  means  as  inductance  or  resistance  again  inserted  in 
the  circuit. 

Control  of  Arc  Travel;  Direction  and  Speed. — The  plate  arc 
terminal  and  the  deposited  metal  follow  the  direction  taken 
by  the  pencil  electrode.  The  difficulty  of  forming  deposits 
varies  with  the  direction.  The  first  exercise  should  consist  in 
forming  a  series  of  deposits  in  different  directions,  as  shown 
in  A,  Fig.  37,  until  the  operator  develops  the  ability  to  form 
a  series  of  straight,  smooth-surfaced  layers.  Additional  skill 
may  be  acquired  by  the  practice  of  forming  squares,  circles 
and  initials. 

The  speed  of  arc  travel  determines  the  height  of  the  deposit 
above  the  parent  metal.  A  second  exercise  should  require  the 
formation  of  deposit  strips  having  heights  of  yie,  a/8  and 
Vie  in-  The  normal  height  of  a  deposit  when  using  a  welding 


52 


ELECTRIC   WELDING 


'current  of  150  amp.  and  a  bare  electrode  of  5/32  in.  diameter 
is  approximately  -J  in. 

Weaving. — If  the  electrode  end  is  made  to  describe  the  arc 
of  a  circle  across  the  direction  of  deposit  formation,  the  width 
of  the  deposit  may  be  increased  without  changing  the  height 
of  the  deposit.  This  weaving  movement  also  facilitates  slag 
notation  and  insures  a  more  complete  fusion  of  the  deposited 
metal  to  the  parent  metal.  B  and  C,  Fig.  37,  illustrate  the 
appearance  of  deposits  formed  with  and  without  weaving  of 
the  electrode. 

A  third  exercise  should  consist  in  forming  layers  of  equal 


A  B  C 

FIG.  37. — Control  of  Arc  Direction  Exercise. 

(A)  Exercise  to  develop  control  of  arc  direction.  (B)  Effect  of  weaving  elec- 
trode across  direction  of  deposit.  (C)  Effect  of  not  weaving.  These  deposits  were 
formed  with  the  operator  and  plate  in  the  same  relative  position,  necessitating  a 
change  in  the  direction  of  arc  travel  for  the  deposition  of  each  layer.  Note  that 
this  direction  is  indicated  by  the  position  of  the  crater  terminating  each  strip  as 
well  as  by  the  inclination  of  the  scalloped  surface. 

heights,  but  having  widths  of  J,  f,  J  and  f  in.  when  using  an 
arc  current  of  150  amp.  and  a  5/32-in.  diameter  bare  electrode. 

As  the  welder  should  now  be  able  to  control  direction, 
height  and  width  of  deposits  while  maintaining  a  short  arc, 
he  should  be  given  the  fourth  exercise  of  forming  tiers  of 
parallel,  overlapping  layers  until  inspection  of  the  surface  and 
cross-sections  of  the  built-up  material  indicates  good  fusion 
of  the  metal  as  well  as  absence  of  slag  and  blowholes. 

Arc  and  Fusion  Characteristics. — The  arc  is  the  welder's 
tool.  Its  function  is  to  transform  electrical  energy  into  highly 


TRAINING  ARC  WELDERS  53 

concentrated  thermal  energy.  This  concentrated  energy  serves 
to  melt  both  the  parent  and  the  deposited  metals  at  the  elec- 
trode terminals,  the  arc  conveying  the  liquefied  pencil  into  the 
crater  formed  on  the  material  to  be  welded. 

The  plate  arc  terminal  will  always  appear  as  a  crater  if 
a  welding  current  is  used.  This  crater  is  formed  partly  by  the 
rapid  volatilization  of  the  liquefied  material  and  partly  by  the 
expulsion  of  fluid  metal  due  to  the  explosive  expansion  of 
occluded  gases  suddenly  released  or  of  gases  formed  by 
chemical  reaction  between  electrode  materials  and  atmospheric 
gases.  To  secure  good  fusion  the  deposited  metal  should  be 
dropped  into  the  crater.  This  is  facilitated  by  the  use  of  a 
short  arc.  .  On  welding,  the  operator  should  frequently  note 
the  depth  of  arc  crater  and  manipulate  the  arc  so  that  the 
advancing  edge  of  the  crater  is  formed  on  the  parent  metal 
and  not  on  the  hot  deposited  metal. 

Polarity. — When  using  bare  electrodes  the  concentration  of 
thermal  energy  is  greater  at  the  positive  than  at  the  negative 
terminal.  Since  in  most  welding  applications  the  joint  has  a 
greater  thermal  capacity  than  the  pencil  electrode,  more  com- 
plete fusion  is  assured  by  making  the  former  the  positive  elec- 
trode. The  difference  in  concentration  of  thermal  energy  may 
be  readily  illustrated  to  the  welder  by  having  him  draw  an 
arc  from  a  Vie-in,  thick  plate  with  the  plate  first  connected 
to  a  negative  and  then  to  the  positive  terminal.  If  a  current 
of  approximately  60  amp.  is  used  with  a  V16-in.  diameter  elec- 
trode, he  will  be  able  to  form  a  deposit  on  the  plate,  if  the 
plate  is  the  negative  terminal.  On  reversing  the  polarity,  how- 
ever, the  energy  concentration  will  be  sufficient  to  melt  through 
the  plate,  thus  producing  a  "cutting  arc." 

An  arc  stream  consists  of  a  central  core  of  electrically 
charged  particles  and  an  envelope  of  hot  gases.  The  electrode 
material  is  conveyed  in  both  liquid  and  vapor  form  across  the 
arc,  a  spray  of  small  globules  being  discernible  with  some  types 
of  electrodes.  Since  atmospheric  gases  tend  to  diffuse  through 
this  incandescent  metal  stream,  it  is  obvious  that  some  of  the 
conveyed  material  becomes  oxidized. 

Through  the  maintenance  of  a  short  arc,  not  exceeding  -J 
in.,  the  resulting  oxidation  is  a  minimum  because  enveloping 
oxide  of  manganese  vapor  and  carbon  dioxide  gas,  formed  by 


54 


ELECTRIC  WELDING 


the  combination  of  atmospheric  oxygen  with  the  manganese 
and  carbon  liberated  from  the  electrodes,  serves  as  a  barrier 
to  restrict  the  further  diffusion  of  atmospheric  gases  into  the 
arc  stream.  Fig.  38  illustrates  the  degree  of  protection  afforded 
the  conveyed  metal  when  using  short  and  long  arcs.  With  the 
latter  convection  currents  deflect  the  protecting  envelope  from 
the  arc  stream.  The  effect  of  arc  length  on  rate  of  oxidation 
may  be  clearly  indicated  to  the  welder  by  forming  deposits  with 
a  |-in.  arc  and  a  f -in.  arc  on  a  clean  plate. 

The  surface  of  the  first  deposit  will  be  clean  and  smooth, 
as  shown  at  a,  Fig.  39.  The  surface  of  the  second  deposit  will 
be  irregular  and  covered  with  a  heavy  coating  of  iron  oxide, 
as  shown  at  &.  All  oxide  formed  during  welding  should  be 


FIG.  38. — Long  and  Short  Welding  Arc. 
Large  arc  stream  causes  excessive  oxidation. 

floated  to  the  surface,  since  its  presence  in  the  weld  will  reduce 
the  strength,  ductility  and  resistance  to  fatigue  of  the  joint. 
Stability. — The  ease  of  maintaining  an  arc  is  determined  by 
the  stabilizing  characteristics  of  the  electrical  circuit  and  the 
arc  gase3.  As  noted  above,  increased  stability  may  be  obtained 
by  the  use  of  series  inductance  or  higher  circuit  voltage  with 
increased  series  resistance,  higher  arc  currents  and  covered 
electrodes.  A  high-carbon-content  electrode,  such  as  a  drill 
rod,  gives  a  less  stable  arc  than  low-carbon  content  rods,  owing 
apparently  to  the  irregular  formation  of  large  volumes  of  arc- 
disturbing  carbon-dioxide  gas.  Bare  electrodes  after  long  ex- 
posure to  the  atmosphere  or  immersion  in  weak  acids  will  be 
found  to  "splutter"  violently,  increasing  thereby  the  difficulty 
of  arc  manipulation.  This  "spluttering"  is  apparently  caused 


TRAINING  ARC  WELDERS 


55 


by  irregular  evolution  of  hydrogen.    If  the  electrode  is  coated 
with  lime,  its  stability  improves. 

The  evident  purpose  of  a  welding  process  is  to  secure  fusion 
between  the  members  welded.  The  factors  that  determine 
fusion  in  arc  welding  are  arc  current,  electrode  current  density, 
thermal  capacity  of  joint  sections  and  melting  temperatures 
of  electrode  and  plate  materials.  By  observing  the  contour 
of  the  surface  of  the  deposited  metal  as  well  as  the  depth  of 
the  arc  crater  the  welder  may  determine  at  once  whether  such 
conditions  under  his  control  as  arc  current,  electrode  current 


FIG.  39 Deposit  Obtained  with  Short  Are  and  Long  Arc. 

Note   that   surfaces  of  deposit  and  plate  in    (a)    are   comparatively   clean,   while 
those  in  (&)  are  heavily  coated  with  iron  oxide. 

density  and  electrode  material  are  properly  adjusted  to  produce 
fusion. 

The  fifth  exercise  should  consist  of  forming  a  series  of 
deposits  with  arc  currents  of  100,  150  and  200  amp.,  using 
electrodes  with  and  without  coatings  having  different  carbon 
and  manganese  content.  Cross-sections  of  the  deposits  should 
then  be  polished  and  etched  with  a  10  per  cent  nitric-acid 
solution  and  the  surface  critically  examined  for  such  evident 
fusion  characteristics  as  penetration  and  overlap,  comparing 
these  with  the  surface  characteristics. 


56 


ELECTRIC  WELDING 


FIG.  40. — Overlap  and  Penetration  Studies. 

(A)  Typical    section    through    a    normal    layer    formed   by    depositing    metal    from 
a  mild- steel  electrode  on  a  mild-steel  plate.     Note  the  contour  of  the   deposit  as  well 
as  that  of  the  fused  zone  and  the  slight  overlap  and  correct  depth  of  deposit  pene- 
tration.    Parent-metal  crystal  structure  is  altered  by  thermal  changes. 

(B)  Typical    section   through   a   deposit   formed    when    holding    a   long   arc.      Ex- 
cessive  overlap  and   no   penetration   exist.      Most   weld   failures  may   be   attributed   to 
the  operator  maintaining  occasionally  or  continuously  too  long  an  arc. 

(C)  Section  through  crater  formed  on  completing  deposit  strip.     The  depth  of  the 
crater  is  a  measure  of  the  depth  of  penetration. 

(D)  Excessive    overlap    secured    with    a    pencil    electrode     (drill    rod)    having    a 
lower   melting   temperature   than   the    parent  metal    (mild    steel). 

(E)  Elimination    of    overlap    obtained    by    using    a   pencil    electrode    (mild    steel) 
having  a  higher  melting  temperature  than  the  parent  metal  (cast  iron). 

(F)  Incomplete  fusion  obtained  with  a  low  arc  current. 

(G)  "Cutting"   secured  through  use  of  high  arc  current. 

(E)  Section  indicates  proper  selection  of  welding  current  and  electrode  diameter 
to  secure  fusion. 

(/)  Poor  fusion  caused  by  too  rapid  flow  thermal  energy  from  deposit  through 
plates. 

(/)  Adequate  fusion  obtained  by  increasing  arc  terminal  energy  to  compensate  for 
increased  rate  of  heat  flow. 


TRAINING  ARC   WELDERS  57 

Overlap  and  Penetration. — Examination  of  the  boundary 
line  between  the  deposited  and  plate  metals  in  A  and  B,  Fig. 
40,  reveals  that  the  penetration  decreases  in  both  directions 
from  the  center  of  the  layer,  no  fusion  being  evident  at  the 
edges  of  the  deposit,  the  contour  betraying  the  extent  of  this 
overlap.  As  shown  in  C  the  penetration  may  be  estimated  from 
the  crater  depression. 

An  exaggerated  overlap  obtained  in  welding  a  mild-steel 
plate  with  a  high-carbon-content  steel  rod,  having  a  lower  melt- 
ing point  than  the  plate,  is  shown  in  D.  The  re-entrant  angle 
of  the  deposit  edge  is  plainly  evident.  E  illustrates  a  condi- 
tion of  no  overlap  in  depositing  metal  from  a  mild-steel  elec- 
trode upon  a  cast-iron  plate  having  a  lower  melting  point. 
F  and  G  show  respectively  the  effect  of  using  too-low  and  too- 
high  arc  currents. 

The  effect  of  heat  conductivity,  heat-storage  capacity,  ex- 
pansion and  contraction  of  the  parent  metal  and  contraction 
of  the  hot-deposit  metal  must  be  studied. 

Heat  Conductivity  and  Capacity. — The  effect  of  any  of 
these  factors  is  to  increase  the  flow  of  thermal  energy  from  the 
plate  arc  terminal  and  therefore  to  reduce  the  amount  of  metal 
liquefied.  To  maintain  a  given  rate  of  welding  speed  it  there- 
for becomes  necessary  to  increase  the  arc  current  with  increase 
in  thickness  or  area  of  joint. 

A  welding  current  of  150  amp.  will  produce  satisfactory 
penetration  on  welding  the  apex  of  scarfed  plates  ^  in.  thick 
shown  in  H.  If  the  joint  is  backed  by  a  heavy  steel  plate, 
increasing  thereby  both  its  thermal  capacity  and  conductivity, 
a  higher  current,  in  the  neighborhood  of  175  amp.  to  200  amp., 
will  be  required  for  the  same  penetration.  If  a  lap  joint  is 
made  as  in  /  and  the  same  current  used  as  in  H,  the  flow  of 
heat  will  be  so  rapid  that  poor  fusion  will  result.  By  increas- 
ing the  current  to  225  amp.,  J,  the  desired  penetration,  as 
indicated  by  crater  depth,  will  be  obtained  with  the  main- 
tenance of  a  high  welding  speed. 

Expansion  and  Contraction  of  Parent  Metal. — The  welding 
operation  necessarily  raises  the  temperature  of  the  metal  adja- 
cent to  the  joint,  producing  strains  in  the  structure  if  it  does 
not  expand  and  contract  freely.  This  condition  is  particularly 
marked  when  welding  a  crack  in  a  large  sheet  or  plate.  The 


58  ELECTRIC   WELDING 

plate  in  the  region  of  the  welded  section  expands,  the  strains 
produced  react  on  the  cold  metal  at  the  end  of  the  crack 
to  open  it  further,  with  the  result  that  as  the  welding  proceeds 
the  plate  continues  to  open  at  a  rate  about  equal  to  the  welding 
speed.  One  inexperienced  welder  followed  such  an  opening  for 
7  ft.  before  adopting  preventive  measures.  The  simplest  of 
these  is  to  drill  a  hole  at  the  end  of  the  crack  and  follow  an 
intermittent  welding  procedure  which  will  maintain  the  plate 
at  a  low  temperature.  Under  exceptional  conditions,  such  as 
welding  cracks  in  heavy  cast-iron  plates  or  cylinders,  it  is 
advisable  to  preheat  and  anneal  the  regions  stressed.  A  second 
example  is  offered  by  the  warping  obtained  on  building  up  the 
diameter  of  a  flanged  shaft.  The  face  of  the  flange  adjacent 
to  the  shaft  becomes  hotter  than  that  opposite,  producing 
internal  stresses  which  warp  the  flange  to  a  mushroom  shape. 
Preheating  of  the  flange  will  prevent  this. 

Contraction  of  Deposited  Metal. — The  contraction  of  de- 
posited metal  is  the  most  frequent  cause  of  residual  stress  in 
welds  and  distortion  of  the  members  welded.  The  magnitude 
of  "locked-in"  stresses  depends  upon  the  welding  procedure 
and  the  chemical  constituents  of  parent  and  deposited  metals. 
If  the  deposit  is  thoroughly  annealed,  practically  no  stress  will 
remain.  On  adopting  a  welding  sequence  in  which  the  joint 
is  formed  by  running  tiers  of  abutting  layers,  each  newly 
applied  layer  will  serve  partly  to  anneal  the  metal  in  adjacent 
layers.  If  mild-steel  plate,  with  less  than  0.20  per  cent  carbon, 
is  welded  in  this  way,  the  locked-in  stresses  should  be  less  than 
5,000  Ib.  per  square  inch.  With  increase  in  carbon  content  the 
locked-in  stresses  will  increase.  If  welded  joints  of  high-carbon 
steels  are  not  permitted  to  cool  slowly,  they  will  often  fall 
apart  when  the  joint  is  given  a  sharp  blow. 

To  illustrate  this  characteristic,  the  following  exercises  are 
suggested : 

Exercise  1 — Deposit  a  layer  1  ft.  long  on  a  strip  of  steel 
about  Vie,  in-  thick,  x/2  in.  wide,  using  150  amp.  direct  current 
and  a  5/32-in.  bare  electrode.  The  longitudinal  contraction  of 
the  deposit  will  bend  the  strip  of  metal  as  shown  in  Fig.  41. 

Exercise  2 — Oeposit  a  layer  of  metal  around  the  periphery 
of  a  wrought-iron  tube.  The  contraction  of  the  deposit  will 
cause  the  tube  to  decrease  in  diameter. 


TRAINING  ARC   WELDERS 


59 


Exercise  3 — Place  two  plates,  J  in.  thick,  2  in.  wide,  6  in. 
long,  -J-  in.  apart,  and  deposit  a  layer  of  metal  joining  them 
together.  The  transverse  contraction  on  cooling  will  pull  the 
plates  out  of  line. 


FIG.  41. — Warping   of  the   Parent  Metal  Caused  by  the   Transverse   Con- 
traction of  the  Deposited  Layers. 


^W  FR££  DISTANCE  ON 
COOLING  OF  DEPOSIT 


-ORIGINAL 
DISTANCE" 


FIG.  42. — Reduction  of  "Free  Distance"  Caused  by  Transverse  Contraction. 

Illustrates  the  necessity  of  rigidly  clamping  the  joint  members,  or  of  assembling 
them  by  an  increasing  distance  from  the  end  to  be  first  welded,  to  equalize  the 
movement  caused  by  the  contraction  of  the  deposited  metal,  if  the  desired  "free 
distance"  is  to  be  maintained  throughout  the  welding  operation. 

Exercise  4 — If  two  plates,  ^  in.  thick,  6  in.  wide  and  6  in. 
long,  spaced  -J  in.,  are  welded  by  depositing  a  short  layer 
extending  J  in.  from  the  one  end,  it  will  be  found  that  when 


60 


ELECTRIC  WELDING 


the  deposit  has  cooled  the  resulting  transverse  contraction  will 
not  only  warp  the  plates  as  in  Exercise  3,  but  will  also  draw 
them  together  as  shown  in  Fig.  42,  thereby  decreasing  the  free 
distance  between  plates. 

Welding  Procedure.— Satisfactory  welds  will  be  obtained 
only  when  the  sections  to  be  welded  are  properly  scarfed  or 
cut  out  and  the  surfaces  on  which  the  deposits  are  formed 
cleaned  before  and  during  the  welding  operation.  The  scarfs 
may  be  machined  or  cut  with  a  cold  chisel  or  the  carbon  arc. 
The  surfaces  of  the  deposited  layers  may  be  cleaned  with  a 


FIG.  43. — Welds  Showing  Poor  and  Good  Fusion. 

Section  through  one-half  of  a  welded  joint  showing  poor  fusion  obtained  at  apex 
of  V  as  the  result  of  assembling  the  joint  sections  without  a  "free  distance."  Section 
through  one-half  of  a  welded  joint  showing  excellent  fusion  obtained  as  a  result 
of  the  use  of  a  "free  distance"  of  |  in.,  thus  permitting  the  operator  to  maintain  a 
short  arc  when  welding  the  bottom  of  the  V.  Failures  of  deep  welds  may  be  usually 
attributed  to  the  use  of  too  small  a  "free  distance,"  low  welding  current,  improper 
cleaning  of  scarf  faces  or  incomplete  slag  flotation. 

chisel  or  wirebrush,  although  the  use  of  a  sandblast  is  prefer- 
able. The  joint  sections  should  be  separated  by  a  free  distance 
of  about  J  in.  in  order  that  the  bottom  of  the  V  may  be  acces- 
sible to  the  welder. 

The  scarf  angle  and  free  distance  vary  inversely.  Both 
are  determined  by  the  depth  of  the  V.  If  the  character  of  the 
work  is  such  that  it  is  not  practicable  to  separate  the  joint 
sections,  the  V  should  be  cut  at  the  bottom  to  form  a  90-dcg. 
angle,  this  angle  being  reduced  to  60  deg.  as  the  surface  is 
approached;  otherwise  the  scarf  angle  may  be  reduced  along 
the  entire  length  to  60  deg.,  excepting  in  the  case  of  very  deep 


TRAINING   ARC   WELDERS  61 

welds.  It  is  usual  practice  now  to  scarf  plate  welds  to  60  deg. 
and  separate  the  sections  -J  in.  for  V's  up  to  \  in.  in  depth. 

At  the  left  in  Fig.  43  is  shown  the  poor  fusion  obtained 
at  the  bottom  of  the  V  on  welding  a  1-in.  square  bar,  scarfed 
60  deg.,  without  the  use  of  a  free  distance.  At  the  right  is 
shown  the  satisfactory  union  obtained  with  the  use  of  free 
distance  of  -J  in.  Whenever  a  butt  joint  is  accessible  to  hori- 
zontal welding  from  both  sides,  it  is  preferable  to  scarf  the 
sections  to  a  double-bevel,  double-V  joint. 

The  choice  of  arc  current  is  determined  by  the  thermal 
conductivity  and  capacity  of  the  joint  as  previously  discussed, 
a  convenient  criterion  being  the  depth  of  arc  crater.  The 
arc  current  selected  should  be  of  such  a  value  that  on  welding 
the  given  sections  the  depth  of  the  arc  crater  or  "bite"  is 
never  less  than  Y16  in- 

Electrode  Current  Density. — To  maintain  a  uniform  flow 
of  the  metal,  neither  too  slow,  which  causes  excessive  penetra- 
tion, nor  too  fast,  which  produces  excessive  overlap,  an  elec- 
trode diameter  should  be  chosen  such  that  the  current  density 
is  approximately  8,000  amp.  per  square  inch.  For  the  usual 
sizes  of  bare  wire  available  this  corresponds  to  the  following 
welding  currents : 

r Arc  Current    (Amp.) \          Electrode 

Normal  Maximum          Minimum  Diameter   (in.) 

225  275  190  3/16 

155  190  125  5/32 

100  125  70  1/8 

60  70  45  3/32 

If  covered  electrodes  are  used,  the  direct-current  rating  for 
the  wires  should  be  decreased  roughly  to  60  per  cent  of  these 
values.  If  bare  wires  are  used  on  alternating  current,  the 
rating  should  be  increased  from  20  to  40  per  cent. 

The  first  layer  should  thoroughly  fuse  the  apex  of  the  V. 
Wherever  possible  inspect  the  reverse  side,  as  the  deposited 
metal  should  appear  projecting  through.  Subsequent  layers 
should  be  fused  then  to  the  preceding  layers  or  to  the  scarfed 
face.  The  final  surface  should  be  from  Vie  to  1/8  in.  above 
that  of  the  adjacent  sections.  This  welt  increases  the  strength 
of  the  joint  or  permits  the  joint  surface  to  be  machined  to  a 
smooth  finish.  If  the  weld  is  to  be  oil-tight,  the  metal  project- 


62  ELECTRIC  WELDING 

ing  through  the  abutting  sections  on  the  reverse  side  as  a  result 
of  the  first  step  in  filling  the  section  should  be  chipped  out 
and  the  resulting  groove  filled  with  at  least  one  layer  of 
deposited  metal.  This  extension  of  the  procedure  is  frequently 
used  in  the  welding  of  double-bevel  joints  where  the  joint  is 
to  have  a  "100  per  cent"  strength. 

If  a  vertical  seam  is  to  be  welded,  sufficient  material  should 
first  be  deposited  to  produce  a  shoulder  so  that  the  added 
metal  may  be  applied  on  an  almost  horizontal  surface  to  facili- 
tate the  welding  operation, 

If  an  overhead  seam  is  to  be  welded,  the  operation  is  sim- 
plified by  placing  on  the  upper  side  of  the  joint  a  heavy  steel 
plate  covering  the  apex  of  the  V.  A  shoulder  is  then  formed 
by  an  initial  deposit  of  metal,  the  operator  continuing  to  add 
metal  to  the  corner  so  produced  and  the  vertical  face  of  the 
shoulder. 

The  considerations  pointed  out  under  the  section  on  thermal 
characteristics  determine  whether  it  is  necessary  to  preheat 
and  anneal  the  joint.  The  method  used  in  filling  the  scarfed 
section  is  determined  by  the  preference  for  either  the  rigid  or 
non-rigid  system. 

When  using  the  rigid  system  both  sections  of  the  joint  are 
clamped  firmly  to  prevent  either  member  from  moving  under 
the  stresses  produced  by  the  expansion  and  contraction  ob- 
tained during  the  welding  operation.  If  a  proper  welding 
sequence  is  not  followed,  the  accumulation  of  "locked-in" 
stresses  on  cooling  may  be  sufficient  to  rupture  the  welded 
area.  To  minimize  these  stresses  it  is  the  usual  practice  to 
tack  the  plates  together  at  the  apex  of  the  scarf  with  short 
deposits  at  about  1-ft.  intervals,  and  then  to  deposit  single 
layers  in  alternate  gaps,  each  tier  being  completed  before  add- 
ing a  second  tier  at  any  section.  This  procedure  tends  to 
maintain  a  low  average  temperature  of  the  joint  and  plate, 
thereby  decreasing  the  amount  of  expansion,  while  the  deposi- 
tion of  the  metal  in  layers  serves  partly  to  anneal  the  metal 
beneath  and  materially  reduce  "locked-in"  stresses. 

In  the  non-rigid  system  both  members  of  the  joint  are  free 
to  move.  To  prevent  the  edges  of  the  plate  from  overlapping 
or  touching  as  shown  in  Fig.  42,  the  initial  free  distance  is  made 
great  enough  to  equalize  the  movement  of  the  plates  caused 


TRAINING   ARC   WELDERS  63 

by  the  contraction  of  the  hot  deposited  metal.  On  welding 
long  seams  of  J-in.  plate  the  contraction  is  limited  by  main- 
taining a  spacing  block  5/ie  in-  wide,  approximately  1  ft.  ahead 
of  the  welded  section.  With  a  "free  distance"  of  J  in.  the 
contraction  stresses  draw  the  plates  together  a  distance  of 
3/10  in.  This  modification  converts  the  non-rigid  into  a  semi- 
rigid system. 

Inspection. — No  direct,  non-destructive  means  are  available 
for  readily  determining  the  strength  and  ductility  of  welds. 
A  number  of  indirect  methods,  however,  are  in  commercial 
use  which  give  a  fair  measure  of  weld  characteristics  if  intel- 
ligently applied.  They  consist  in  estimating  the  degree  of 
fusion  and  porosity  present  by  critically  inspecting  the  surface 
of  each  layer  and  in  noting  the  depth  of  liquid  penetration 
through  the  completed  section. 

In  examining  each  layer  the  amount  of  oxide  present, 
smoothness  and  regularity  of  the  surface,  its  contour,  freedom 
from  porosity  and  depth  of  crater  should  be  noted.  After  a 
little  experience  these  observations  will  give  the  inspector  a 
good  indication  of  the  manipulative  ability  of  the  welder  and 
of  the  degree  of  fusion  obtained,  as  discussed  above. 

A  succession  of  unfused  zones  will  produce  a  leaky  joint. 
These  sections  may  be  detected  by  flooding  one  surface  of 
the  joint  with  kerosene,  using  a  retaining  wall  of  putty,  if 
necessary,  as  the  liquid  penetrates  through  the  linked  areas 
and  emerges  to  stain  the  opposite  side. 

Brief  Terminology. — The  following  terms  are  used  most 
frequently  in  arc  welding: 

Free  distance. — The  amount  that  the  joint  sections  are  separated  before 
welding. 

Overlap. — The  area  of  deposited  metal  that  is  not  fused  to  the  parent 
metal. 

Parent  metal. — The  original  metal  of  the  joint  sections. 

Penetration. — The  depth  to  which  the  parent  metal  is  melted  by  the  arc 
— gaged  by  the  depth  of  the  arc  crater. 

Recession. — The  distance  between  the  original  scarf  line  and  the  average 
depth  of  penetration  parallel  to  this  line  obtained  in  the  completed  weld. 

Ee-entrant  angle. — The  angle  between  the  original  surface  of  the  parent 
metal  and  the  overlapping,  unfused  deposit  edge. 

Scarf. — The  chamfered  surface  of  a  joint. 

Tack. — A  short  deposit,  from  £  to  2  in.  long,  which  serves  to  hold 
the  sections  of  a  joint  in  place. 


64  ELECTRIC  WELDING 

Weaving. — A  semi-circular  motion  of  the  arc  terminal  to  the  right  and 
left  of  the  direction  of  deposition,  which  serves  to  increase  the  width  of 
the  deposit,  decrease  overlap  and  assist  in  slag  flotation. 

Welt. — The  material  extending  beyond  the  surface  of  the  weld  shanks 
to  reinforce  the  weld. 

QUESTIONS   AND  ANSWERS 

What  does  the  welder's  equipment  consist  of? 

Welding  generator,  electrode  holder  with  cables,  welding  booth,  helmet 
or  shield,  gauntlets,  high  shoes  with  bellows  tongue,  heavy  clothing  or 
leather  apron,  proper  electrodes. 

What  is  the  most  important  precaution  the  operator  should  observe? 

To  protect  his  eyes  and  body  from  the  radiant  energy  emitted  by  the 
arc. 

How  is  the  operator  prevented  from  drawing  too  long  an  arc  after 
the  electrode  "freezes"  to  the  work? 

By  twisting  the  wrist  sharply  to  tho  right  or  left,  thereby  shearing  the 
fused  area. 

What   is  the  essential  factor  in  securing  the  maintenance  of  the  arc? 

The  electrode  should  be  advanced  to  the  work  at  the  rate  at  which  it 
is  being  melted. 

What  is  the  test  of  an  operator's  manipulative  ability? 

He  should  be  able  to  hold  an  arc  no  longer  than  J  in.,  having  a  voltage 
across  it  less  than  twenty-five  during  the  period  required  to  deposit  the 
metal  from  a  6/32-in.  diameter  bare  electrode,  12  in.  long  on  150  amp. 
direct  current. 

What  is  meant  by  "free  distance,"  "overlap,"  "parent  metal," 
"penetration,"  "recession,"  "re-entrant  angle,"  "scarf,"  "tack," 
"weaving"  and  "welt"? 

Given  under  ' '  Terminology. ' ' 

What  function  does  the  arc  perform? 

It  transforms  electrical  energy  into  Thermal  energy. 

What  polarity  should  the  welder  use  on  welding  all  but  thin  sections 
with  bare  electrodes? 

The  pencil  electrode  should   be  negative. 

How  may  the  amount  of  oxide  formed  be  reduced  to  a  minimum? 

By  holding  a  short  arc  and  the  use  of  electrodes  containing  a  small 
quantity  of  carbon  (0.18  per  cent)  and  manganese  (0.50  per  cent). 

How  may  an  operator  determine  the  degree  of  fusion  obtained  (a)  by 
inspecting  the  surface,  (b)  by  inspecting  the  cross-section  of  deposit? 

(a)  By   examining   the   contour   of   the   surface,    noting   the   re-entrant 
angle    and    estimating    the    overlap;    observing    the    depth    of    crater    and 
estimating  the  penetration. 

(b)  By  directly  observing   the   depth   of   penetration   of  recession,   the 
overlap  and  porosity  or  blow  holes. 

What  are  the  factors  in  arc  welding  that  determine  the  degree  of 
fusion? 


TRAINING  ARC   WELDERS  65 

Arc  current,  arc  length,  electrode  current  density,  electrode  material, 
freedom  of  weld  from  oxides. 

How  may  a  welder  determine  when  he  is  using  the  proper  welding 
current  ? 

By  the  depth  the  arc  melts  the  material  welded.  The  crater  should 
be  not  less  than  y16  in.  in  depth. 

What  is  the  most  important  thermal  characteristic  encountered  in 
welding? 

Contraction  of  the  hot  deposit. 

How  may  strains  produced  by  this  characteristic  be  minimized? 

By  adopting  a  correct  welding  procedure,  either  non-rigid  or  rigid, 
which  serves  partly  to  anneal  the  metal  and  reduce  "locked-in"  stresses. 

What  is  the  effect  of  holding  too  long  an  arc  with  the  metallic  electrode? 

The  use  of  a  long  arc  produces  a  poor  deposit,  due  to  insufficient 
penetration,  and  also  produces  a  large  amount  of  oxide  which  reduces  both 
the  strength  and  ductility  of  the  joint. 

What  size  of  bare  electrodes  corresponds  to  welding  currents  of 
approximately  225,  155,  100  and  60  amp.  on  welding  with  direct  current? 

Sizes  3/16,  s/32,  1/8  and  3/32  in.  respectively. 

How  should  joint  sections  be  prepared  for  welding? 

The  surfaces  should  be  cleaned  thoroughly  and  the  faces  of  the  joint 
scarfed  to  an  angle  of  60  to  90  degrees  with  the  edges  separated  a  free 
distance  of  approximately  |  in.  in  the  rigid  welding  process,  and  an  addi- 
tional 3/16  in.  per  foot  from  the  point  welded  for  each  foot  length  when 
using  the  non-rigid  system. 

What  surface  characteristics  denote  fusion? 

Surface  porosity,  amount  of  oxide  coating,  depth  of  arc  crater,  surface 
contour,  compactness,  regularity  and  re-entrant  angles. 


CHAPTER   V 
CARBON-ELECTRODE  ARC  WELDING  AND  CUTTING 

In  the  American  Machinist  of  Sept.  9,  1920,  O.  H.  Escholz, 
research  engineer  of  the  Westinghouse  Electric  &  Manufac- 
turing Co.,  dealt  with  the  various  phases  of  carbon  arc  welding 
and  cutting  as  follows: 

Carbon  or  graphite  electrode  arc  welding  is  the  oldest  of 
the  electric  fusion  arc  processes  now  in  use.  The  original 
process  consisted  in  drawing  an  arc  between  the  parent  metal 
and  a  carbon  electrode  in  such  a  manner  that  the  thermal 
energy  developed  at  the  metal  crater  fused  together  the  edges 
of  the  joint  members.  This  process  was  early  modified  by  add- 
ing fused  filling  metal  to  the  molten^  surface  of  the  parent 
metal. 

The  equipment  now  used  consists  of  a  direct-current  arc- 
circuit  possessing  inherent  means  for  stabilizing  the  carbon 
arc,  a  welding  hood  for  the  operator,  an  electrode  holder  that 
does  not  become  uncomfortably  hot  in  service  and  suitable 
clothing  such  as  bellows-tongued  shoes,  gauntlets  and  apron  of 
heavy  material. 

When  arc  currents  of  less  than  200  amp.  are  used,  or  when 
a  graphite  arc  process  is  employed  intermittently  with  the 
metallic  electrode  process,  the  carbon-holding  adapter  shown 
in  Fig.  44  may  be  used  with  the  metallic  electrode  holder,  the 
shank  of  the  adapter  being  substituted  for  the  metal  electrode. 
With  very  high  arc  currents,  750  amp.  or  more,  special  holders 
should  He  constructed  to  protect  the  operator  from  the  intense 
heat  generated  at  the  arc.  Typical  holders  are  shown  in  Figs. 
45  and  46. 

Electrodes. — Although  hard  carbon  was  originally  employed 
for  the  electrode  material,  experience  has  shown  that  a  lower 
rate  of  electrode  consumption  as  well  as  a  softer  weld  may  be 
obtained  by  substituting  graphite  electrodes.  While  both  elec- 

66 


CARBON-ELECTRODE  ARC  WELDING  AND   CUTTING       67 

trodcs  have  the  same  base  and  binder,  the  graphite  electrode 
is  baked  at  a  sufficiently  high  temperature  (2000  deg.  C.)  to 
graphitize  the  binder,  thereby  improving  the  bond  and  the 
homogeneity  of  the  electrode.  The  graphite  electrode  is  readily 


FIG.  44. — Adapters  for  Using  Carbons  in  Metallic-Electrode  Holder 


FIG.  45.— Metallic-Electrode  Holder. 


FIG.  46. — Carbon-  or  Graphite-Electrode  Holder. 

distinguishable  by  its  greasy  "feel"  and  the  characteristic 
streak  it  makes  on  paper. 

The  diameter  of  the  electrode  is  determined  partly  by  the 
arc  current.     To  fix  the  position  of  the  carbon  arc  terminal, 


68  ELECTRIC   WELDING 

thereby  increasing  arc  stability  and  arc  control,  all  electrodes 
should  be  tapered.  This  precaution  is  particularly  important 
when  using  low  valujs  of  arc  current  or  when  maintaining  an 
arc  under  conditions  which  cause  distortion  and  instability. 
The  following  table  gives  electrode  diameters  in  most  common 
use  with  various  arc  currents : 

Amperes  Diameter 

50  to     150  i  in.  tapered  to  |  in. 

150  to     300  |  in.  tapered  to  g  in. 

300  to     500  1     in.  tapered  to  |  in. 

500  to     750  1^  in.  tapered  to  |  in. 

750  to  1000  H  in.  tapered  to  }  in. 

Filler  Material. — A  strong,  sound  weld  can  be  obtained  only 
by  using  for  filler  metal  low-carbon,  commercially  pure  iron 
rods  having  a  diameter  of  f  in.  or  \  in.,  depending  on  the 
welding  current  used.  Cast  iron  or  manganese  steel  filler  rods 
produce  hard  welds  in  which  the  fusion  between  the  parent 
and  added  metals  may  be  incomplete.  Short  rods  of  scrap 
metal,  steel  turnings,  etc.,  are  frequently  made  use  of  for  filler 
metal  when  the  purpose  of  the  welder  is  merely  to  fill  a  hole 
as  rapidly  as  possible.  It  should  be  understood  that  welds 
made  with  such  metal  are  weak,  contain  many  blowholes  and 
are  frequently  too  hard  to  machine. 

It  is  as  difficult  for  the  user  of  graphite  arc  processes  as 
it  is  for  the  oxy-acetylene  welder  to  estimate  the  degree  of 
fusion  obtained  between  deposited  and  parent  metals.  There- 
fore the  operator  must  follow  conscientiously  the  correct  pro- 
cedure, recognizing  that  the  responsibility  of  executing  a  faulty 
weld  rests  solely  with  himself.  He  should,  of  course,  have  a 
working  knowledge  of  metals,  must  be  able  to  distinguish 
colors  and  possess  a  fair  degree  of  muscular  co-ordination, 
although  the  manipulative  skill  required  is  less  than  that  neces- 
sitated by  the  metallic  electrode  process. 

For  graphite  arc  welding  employing  a  filler  the  correct 
posture  is  illustrated  in  Fig.  47.  The  filler  rod  is  shown  grasped 
by  the  left  hand  with  the  thumb  uppermost.  When  held  in 
this  position  the  welder  may  use  the  rod  to  brush  off  slag 
from  the  surface  of  molten  metal  or  to  advance  the  rod  into 
the  arc  stream. 

The  surfaces  to  be  welded  should  be  chipped  clean.    Where 


CARBON-ELECTRODE  ARC   WELDING  AND  CUTTING       69 

they  are  scarfed  the  angle  should  be  wide  enough  to  enable  the 
operator  to  draw  an  are  from  any  point  without  danger  of 
short-circuiting  the  arc.  It  is  the  practice  of  some  welders 
to  remove  sand  and  slag  from  the  metal  surfaces  by  fusing 
them  with  the  aid  of  the  arc  and  then  striking  the  fluid  mass 
with  a  ball-peen  hammer.  This  method  should  be  discouraged 
since  both  operator  and  nearby  workmen  may  be  seriously 
injured  by  the  flying  hot  particles. 

Arc  Manipulation.— The  arc  is  formed  by  withdrawing  the 
graphite  electrode  from  a  clean  surface  of  solid  metal  or  from 
the  end  of  the  filler  rod  when  it  is  held  in  contact  with  the 


m    m    m    BL.J1 

FlG.  47. — Correct  Welding  Position  when  Using  Carbon  Arc  and  a  Filler  Rod. 

j  . 

parent  metal.  If  the  arc  is  formed  from  the  surface  of  the 
deposited  metal  or  from  that  of  a  molten  area,  slag  particles 
may  adhere  to  the  end  of  the  electrode,  deflecting  the  arc  and 
increasing  tfie  difficulty  of  manipulating  it. 

By  inclining  the  electrode  approximately  15  deg.  to  the 
vertical  the  control  of  the  position,  direction  and  speed  of  the 
arc  terminal  is  facilitated.  When  the  electrode  is  held  ver- 
tically irregularities  in  the  direction  and  force  of  convection 
currents  deflect  the  arc  first  to  one  side  and  then  to  another, 
causing  a  corresponding  movement  of  the  metal  arc  terminal. 
By  inclining  the  graphite  electrode  the  deflecting  force  is  con- 
stant in  direction,  with  the  result  that  the  electrode  arc  stream 


70 


ELECTRIC  WELDING 


and  arc  terminal  remain  approximately  in  line,  as  shown  in 
Pig.  48,  and  may  then  be  moved  in  any  direction  or  at  any 
speed  by  a  corresponding  movement  of  the  graphite  electrode. 
Polarity. — It  is  common  knowledge  that  the  positive 
terminal  of  a  carbon  arc  is  hotter  and  consumes  more  energy 
than  the  negative  terminal.  If  the  graphite  electrode  of  the 
welding  arc  is  made  the  positive  terminal,  energy  will  be  use- 


GRAPHITE 
I^Diam.  Negative 


Core,  White 
i-Arc  Sfream,  Blue 


!£'•/•  Arc  F/ctme, 
' 


PARENT      METAL 
Positive 


Fie.  48. — Position  of  Electrode  and  Characteristics  of  the  Arc. 


lessly  consumed  and  the  resulting  higher  temperature  will 
increase  the  loss  of  carbon  through  excessive  oxidation  and 
vaporization.  Moreover,  for  reasons  well  known  to  those 
familiar  with  the  phenomena  of  arc  formation,  a  very  unstable 
arc  is  obtained  with  the  iron  parent  metal  functioning  as  the 
negative  electrode.  The  graphite  electrode  should  therefore 
always  be  connected  to  the  negative  terminal,  reversal  of 


CARBON-ELECTRODE  ARC  WELDING   AND   CUTTING       71 

polarity  being  detected  when  the  arc  is  difficult  to  hold  and 
when  the  carbon  becomes  excessively  hot. 

Arc  Length. — Even  when  the  graphite  electrode  serves  as 
the  negative  arc  terminal,  its  temperature  is  great  enough  to 
cause  vaporization  of  a  considerable  quantity  of  carbon.  If 
this  carbon  is  permitted  to  be  transferred  to  and  absorbed 
by  the  fluid  metal,  a  hard  weld  will  result.  To  insure  a  soft 
metal  practically  all  of  the  volatilized  carbon  should  be  oxid- 
ized. This  may  be  accomplished  by  regulating  the  arc  length 
so  that  atmospheric  oxygen  will  have  ample  time  to  diffuse 
through  the  arc  stream  and  combine  with  all  of  the  carbon 
present.  The  correct  arc  length  is  dependent  upon  the  welding 
current  and  the  degree  of  confinement  of  the  arc.  Since  the 
arc  diameter  varies  as  the  square  root  of  the  current  the  arc 
length  should  be  increased  in  proportion  to  the  square  root  of 
the  current.  It  is  also  obvious  that  when  an  arc  is  drawn 
from  a  flat,  open  surface  the  vaporized  carbon  is  more  acces- 
sible to  the  atmospheric  gases  than  when  it  is  inclosed  by  the 
walls  of  a  blowhole.  This  means  that  to  secure  the  same  amount 
of  oxidized  carbon  under  both  conditions  the  confined  arc 
should  be  the  longer.  Many  welders  are  not  familiar  with 
this  phenomenon,  with  the  result  that  metal  deposited  in  holes 
or  corners  appears  to  be  inexplicably  hard. 

The  length  of  a  250-amp.  arc  should  not  be  less  than  \  in. 
and  that  for  a  500-amp.  arc  should  not  be  less  than  J  in.  when 
drawing  the  arc  from  a  flat  surface.  The  maintenance  of 
excessive  arc  lengths  causes  the  diffusion,  through  convection 
currents,  of  the  protecting  envelope  of  carbon  dioxide,  with 
the  result  that  the  exposed  hot  metal  is  rapidly  oxidized  or 
"burned."  For  most  purposes  a  250-amp.  arc  should  not 
exceed  a  "length  of  1  in.  and  the  length  of  a  500-amp.  arc  should 
not  exceed  \\  in.  In  view  of  the  large  variation  permissible, 
the  welder  should  be  able  to  maintain  an  arc  length  which 
assures  a  soft  weld  metal  with  but  little  slag  content. 

The  arc  serves  to  transform  electrical  energy  into  thermal 
energy.  The  energy  developed  at  the  metal  terminal  or  arc 
crater  is  utilized  to  melt  the  parent  metal,  while  that  generated 
in  the  arc  stream  serves  to  melt  the  filling  material.  If  the 
molten  filler  is  not  properly  guided  and,  as  a  consequence, 
overruns  the  fused  parent  metal,  a  poor  weld  will  result.  This 


72  ELECTRIC  WELDING 

process  necessitates,  therefore,  a  constant  observation  of  the 
distribution  of  the  fused  metals  as  well  as  a  proper  control 
of  the  direction  of  flow  and  speed  of  deposition  of  the  filling 
metal. 

There  are  two  methods  in  use  for  adding  the  filler  with  a 


FIG.  49. — Starting  to  Build  Up  a  Surface. 

minimum  overlap.  One  is  called  the  "puddling"  process.  It 
consists  in  melting  a  small  area  of  the  parent  metal,  thrusting 
the  end  of  the  filler  rod  into  the  arc  stream,  where  a  small 
section  is  melted  or  cut  off,  withdrawing  the  rod  and  fusing 
the  added  material  with  the  molten  parent  metal  by  imparting 


FlG.  50. — Building-Up  Process  Nearly  Completed. 

a  rotary  motion  to  the  arc.  This  puddling  of  the  metals  serves 
also  to  float  slag  and  oxidized  material  to  the  edge  of  the 
fused  area,  where  they  may  be  brushed  or  chipped  off. 

The  rapid  building  up  of  a  surface  by  this  method  is  shown 
in  Fig.  49.     The  short  sections  of  filler  rod  were  welded  to 


CARBON-ELECTRODE  ARC   WELDING  AND  CUTTING       73 

the  sides  of  the  casting  in  order  to  prevent  the  molten  material 
from  overflowing  and  to  indicate  the  required  height  of  the 
addition.  The  appearance  of  the  nearly  completed  "fill"  is 
shown  in  Fig.  50.  One  side  of  the  added  metal  is  lower  than 
the  others  to  facilitate  the  floating  off  of  the  slag,  some  of 


FIG.  51. — Section  Through  a  Built-Up  Weld. 


FIG.  52. — Method  of  Depositing  Filling  Material  in  Layers. 

which  may  be  observed  adhering  to  the  edge  of  the  plate. 
Fig.  51  shows  a  section  through  a  weld  produced  in  this  man- 
ner, the  continuous  line  indicating  the  zone  of  fusion  and  the 
broken  line  the  boundary  of  crystal  structural  change  produced 
by  the  temperature  cycle  through  which  the  parent  metal  has 
passed  as  a  result  of  the  absorption  of  the  arc  energy. 


74 


ELECTRIC   WELDING 


Some  users  of  this  method  advocate  puddling  short  sections 
of  the  filler  rod,  1  to  3  in.  in  length,  with  the  parent  metal. 
Where  this  is  done,  the  filler  may  be  incompletely  fused  and 
therefore  not  welded  to  the  surface  of  the  parent  metal. 

In  the  second  method  the  filler  material  is  deposited  in 


FIG.  53. — Layers  of  Deposits  Smoothed  Over. 


FIG.  54. — Fused  Ends  of  Filler  Rods. 

layers,  as  shown  in  Figs.  52  and  53,  the  deposits  being  similar 
to  those  obtained  with  the  metallic  electrode  process  but  wider 
and  higher.  In  these  examples  a  welding  current  of  250  amp. 
with  a  filling  rod  f  in.  in  dia.  were  used.  This  method  simply 
requires  the  operator  to  feed  the  filling  rod  continuously  into 
the  arc  stream  so  that  the  molten  filler  deposits  on  the  area 


CARBON-ELECTRODE  ARC  WELDING  AND  CUTTING       75 

of  parent  metal  fused  by  the  arc  terminal  while  the  arc  travels 
across  the  surface.  If  the  end  of  the  rod  is  moved  forward 
while  resting  on  the  surface  of  the  newly  deposited  metal, 


FIG.  55. — Showing  the  Fusion  of  Parent  Metal  and  Four  Layers. 

most  of  the  slag  produced  by  the  oxidation  of  the  hot  metal 
is  floated  to  the  sides  of  the  deposit,  where  it  may  be  brushed 
or  chipped  off. 

The  appearance  of  fused  filler  rod  ends  when  correctly 
manipulated  is  shown  in  Fig.  54.     Slag  may  be  observed  still 


Fie.  56. — Flanged  Edges  Welded  with  Graphite  Arc. 

adhering  to  the  bottom  of  one  of  the  rods.  The  fusion  between 
parent  and  added  metal  is  shown  in  Fig.  55.  Four  layers  of 
added  metal  are  shown  at  the  upper  surface. 

To  remove  slag  or  improve  the  appearance  of  the  deposits 


76  ELECTRIC   WELDING 

the  surface  of  the  added  metal  may  be  remelted  by  running 
the  arc  terminal  over  it,  provided  "burning"  and  hardening 
of  the  metal  is  avoided.  Figs.  52  and  53  illustrate  plainly  the 
appearance  of  deposits  before  and  after  the  surfacing  operation. 

The  expedient  of  hammering  or  swaging  the  hot  deposited 
metal  is  frequently  resorted  to  where  a  refinement  in  the  struc- 
ture of  the  crystal  grains  is  desirable. 

Flanged  Seam  Welding. — Fig.  56  illustrates  a  useful  appli- 
cation of  the  original  carbon-arc  process  wherein  no  filler  metal 
is  used,  the  metal  arc  terminal  serving  to  melt  together  the 
flanged  edges. 

This  process  is  easily  performed.  To  obtain  adequate  fusion 
the  arc  current  selected  should  have  such  a  value  that  the 
metal-arc  crater  nearly  spans  the  edges  of  the  seam.  To  assure 
the  maintenance  of  a  stable  arc  a  small,  tapered  electrode 
should  be  employed,  the  diameter  of  the  electrode  end  remain- 
ing less  than  |-in.  during  use. 

This  graphite  arc  process  is  used  occasionally  to  form  butt 
and  lap  welds  by  melting  together  the  sides  of  the  joint  without 
the  use  of  filler  metal.  Examination  of  sections  through  joints 
made  in  this  manner  reveals  that  the  weld  is  very  shallow  and 
therefore  weak. 

Welding  of  Non-Ferrous  Metals. — Copper  and  bronzes  have 
been  successfully  welded  with  the  graphite  arc  when  employ- 
ing a  bronze  filler  rod  low  in  tin  and  zinc  and  high  in  phos- 
phorous, at  least  0.25  per  cent.  The  best  filler  material  for 
the  various  analyses  of  parent  metals  has  not  been  determined, 
but  it  is  recognized  that  the  presence  of  some  deoxidizing  agent 
such  as  phosphorus  is  necessary  in  order  to  insure  sound  welds 
free  from  oxide  and  blowholes.  Since  copper  and  its  alloys 
have  a  high  thermal  capacity  and  conductivity,  preheating  of 
the  structure  facilitates  the  fusion  of  the  joint  surfaces.  The 
grain  of  the  completed  weld  may  be  refined  by  subjecting  the 
metal  to  a  suitable  mechanical  working  and  temperature  cycle. 

Low-melting-point  metals  such  as  lead  may  be  welded  by 
holding  the  graphite  electrode  in  contact  with  the  surfaces  to 
be  fused  without  drawing  an  arc,  the  current  value  used  being 
sufficient  to  heat  the  end  of  the  carbon  to  incandescence.  The 
hot  electrode  tip  may  also  be  used  to  melt  the  filler  rod  into 
the  molten  parent  metal. 


CARBON-ELECTRODE  ARC  WELDING   AND   CUTTING       77 

Application. — The  graphite  arc  processes  may  be  used  for 
the  following  purposes: 

(1)  Welding  of  cast  steel  and  non-ferrous  metals. 

(2)  Cutting  of  cast-iron  and  cast-steel  risers  and  fins  and 
non-ferrous  metals. 

(3)  Rapid  deposition  of  metal  to  build  up  a  surface  or  fill 
in  shrinkage  cavities,  cracks,  blowholes  and  sand  pockets  where 
strength  is  of  minor  importance. 

(4)  Fusion  of  standing  seams. 

(5)  Melting  and  cutting  of  scrap  metal. 

(6)  Remelting  of  a  surface  to  improve  its  appearance  or  fit. 


FIG.  57.  —  Typical  Carbon-Electrode  Cuts  in  £-In.  Ship  Plate. 


(7)  Preheating  of  a  metal  structure  to  facilitate  the  welding 
operation,    to    reduce    locked-in    stresses    or    to    alter    some 
dimension. 

(8)  Deposition  of  hard  metal  or  the  hardening  of  a  surface 
by  the  inclusion  of  vaporized  carbon,  such  as  rails,  frogs  and 
wheel  treads. 

(9)  Automatic  cutting  and  welding  of  sheet  metal. 
Cutting.  —  The  manipulation  of  the  cutting  arc  is  exceed- 

ingly simple,  the  operator  merely  advancing  the  arc  terminal 
over  the  section  to  be  cut  at  a  rate  equal  to  that  at  which 
the  molten  metal  flows  from  the  cut.  The  cutting  speed  in- 


78  ELECTRIC  WELDING 

creases  with  the  value  of  arc  current  used.  The  width  of  the 
cut  increases  with  the  arc  diameter  and  therefore  as  the  square 
root  of  the  arc  current.  Fig.  57  shows  the  appearance  of  cuts 
made  in  ship  steel  plate  £  in.  thick.  The  following  data  apply 
in  this  case : 

Position  of  Cut  Amp.    Width,  in.    Length,  in.    Time,  min. 

Upper    250  0.5  8  2£ 

Lower    650  0.8  8  1 

Before  cutting  this  plate  the  welder  outlined  the  desired 
course  of  the  cut  by  a  series  of  prick-punch  marks. 

When  cutting  deeper  than  4  in.  the  electrode  should  not 
come  in  contact  with  the  walls  of  the  cut  and  thereby  short- 
circuit  the  arc. 

This  process  may  be  used  for  cutting  both  ferrous  and  non- 
ferrous  metals.  It  has  found  a  particularly  useful  field  in  the 
cutting  of  cast  iron.  It  is  often  used  for  the  "  burning "  out 
of  blast-furnace  tap  holes  and  the  melting  or  cutting  of  iron 
frozen  in  such  furnaces. 

CUTTING    METALS 

The  accompanying  charts  illustrate  the  application  of  the 
carbon  electrode  cutting  process  with  a  current  value  of  350 
to  800  amperes,  depending  on  the  thickness  of  the  metal  and 
the  speed  of  cutting  desired.  A  moderate  cutting  speed  is 
obtained  at  a  small  operating  expense,  adapting  it  particularly 
for  use  in  foundries  for  cutting  off  risers,  sink  heads,  for  cut- 
ting up  scrap,  and  general  work  of  this  nature  where  a  smooth 
finish  cut  is  not  essential. 

The  cross  section  of  these  risers,  etc.,  is  frequently  of  con- 
siderable area,  but  by  the  use  of  the  proper  current  value, 
they  may  be  readily  removed. 

Table  IV  shows  the  results  obtained  from  tests  in  cutting 
steel  plate  with  the  electric  arc.  The  curves  show  the  rate 
of  cutting  cast  iron  sections  of  various  shapes.  Fig.  58  shows 
the  rate  of  cutting  cast  iron  plates.  Fig.  59  circular  cross 
sections,  and  Fig.  60  square  blocks.  The  curves  are  based  on 
data  secured  through  an  extensive  series  of  observations. 


CARBON-ELECTRODE  ARC   WELDING   AND   CUTTING       79 


FIG.  58. — Eate  of  Cutting  Cast  Iron  Plates. 


10      20     30      40      50      60      70      SO 

I          I  1-M.ntatcs    |  |  |  | 


FIG.  59. — Rate  of  Cutting  Cast  Iron  of  Circular  Cross  Section. 


-^ 

^ 

*^^ 

\^^ 

^ 

,x^ 

^ 

^ 

x 

^ 

L] 

X 

X 

<*  8 
lA 

/ 

rh 

°r~i 

9      2 

0     3 

0     4 

0     5 

0      6 
1 

0  7 

hinute 

o    a 

1 

0     9 

9     1( 

K)    1 

0    1. 

20   1 

30 

Fie.  60.— Rate  of  Cutting  Cast  Iron  Square  Blocks. 


80  ELECTRIC  WELDING 

TABLE  IV. — CUTTING  STEEL  PLATES  WITH  THE  CARBON  ARC 


Thickness 

Current 

Speed  Minutes 

in  Inches 

in  Amps. 

Per  Ft. 

Kw.-Hrs.  Per  Ft. 

1 

400 

.50 

.312 

i 

400 

1.20 

.75 

1 

400 

2.14 

1.34 

1 

400 

3.00 

1.88 

1 

600 

3.75 

3.50 

H 

600 

4.32 

4.10 

2 

600 

6.75 

6.30 

4 

600 

16.90 

15.50 

6 

800 

29.00 

36.20 

8 

800 

40.50 

50.00 

10 

800 

59.00 

74.00 

12 

800 

65.00 

82.00 

CHAPTER   VI 
ARC    WELDING    PROCEDURE 

It  is  presumed  that  the  welder  has  a  fair  knowledge  of 
the  different  processes  of  both  carbon  and  metallic  arc  weld- 
ing, gained  from  reading  the  previous  chapters  or  from  actual 
experience.  However,  we  will  recapitulate  to  some  extent 
in  order  to  make  everything  as  clear  as  possible.  Then  we  shall 
give  some  examples  of  the  proper  procedure  in  making  welds 
of  various  kinds.  For  the  descriptions  and  drawings  we  are 
principally  indebted  to  the  Westinghouse  Electric  and  Manu- 
facturing Co.,  the  Lincoln  Electric  Co.,  and  the  Wilson  Welder 
and  Metals  Co. 

In  order  to  prepare  the  metal  for  a  satisfactory  weld,  the 
entire  surfaces  to  be  welded  must  be  made  readily  accessible 
to  the  deposit  of  the  new  metal  which  is  to  be  added.  In 
addition,  it  is  very  essential  that  the  surfaces  are  free  from 
dirt,  grease,  sand,  rust  or  other  foreign  matter.  For  this 
service,  a  sandblast,  metal  wire  brush,  or  cold  chisel  are  recom- 
mended. 

During  the  past  few  years  great  progress  has  been  made 
in  the  improvement  of  steels  by  the  proper  correlation  of 
heat  treatment  and  chemical  composition.  The  characteristics 
of  high-carbon  and  alloy  steels,  particularly,  have  been  radically 
improved.  However,  no  amount  of  heat  treatment  will  appre- 
ciably improve  or  change  the  characteristics  of  medium  and 
low-carbon  steels  which  comprise  the  greatest  field  of  applica- 
tion for  arc  welding.  Furthermore,  the  metal  usually  deposited 
by  the  arc  is  a  low-carbon  steel  often  approaching  commercially 
pure  iron.  It  must  be  evident  therefore  that  the  changes  of 
steel  structure  due  to  the  arc-welding  process  will  not  be 
appreciable  and  also  that  any  subsequent  heat  treatment  of 
the  medium-  or  mild-steel  material  will  not  result  in  improve- 
ments commensurate  with  the  cost. 

81 


82  ELECTRIC  WELDING 

Pre-heating  of  medium  and  mild  steel  before  applying  the 
arc  is  not  necessary  and  will  only  enable  the  operator  to  make 
a  weld  with  a  lesser  value  of  current. 

Cast-iron  welds  must  be  annealed  before  machining  other 
than  grinding  is  done  in  the  welded  sections.  This  is  necessary 
because  at  the  boundary  between  the  original  cast  iron  and 
the  deposited  metal  there  will  be  formed  a  zone  of  hard,  high- 
carbon  steel  produced  by  the  union  of  carbon  (from  the  cast 
iron)  with  the  iron  filler.  This  material  is  chilled  quite  sud- 
denly after  the  weld  is  made  by  the  dissipation  of  the  heat 
into  the  surrounding  cast  iron  which  is  usually  at  a  com- 
paratively low  temperature. 

Although  it  is  not  absolutely  necessary  to  pre-heat  cast  iron 
previous  to  arc  welding,  this  is  done  in  some  instances  to 
produce  a  partial  annealing  of  the  finished  weld.  The  pre- 
heating operation  will  raise  the  temperature  of  a  large  portion 
of  the  casting.  When  the  weld  is  completed,  the  heat  in  the 
casting  will  flow  into  the  welded  section,  thereby  reducing  the 
rate  of  cooling. 

Arc  Length. — The  maintenance  of  the  proper  arc  length  for 
the  metallic  electrode  process  is  very  important.  With  a  long 
arc  an  extended  surface  of  the  work  is  covered  probably  caused 
by  air  drafts  with  the  result  that  there  is  only  a  thin  deposit 
of  the  new  metal  with  poor  fusion.  If,  however,  the  arc  is 
maintained  short,  much  better  fusion  is  obtained,  the  new 
metal  will  be  confined  to  a  smaller  area,  and  the  burning  and 
porosity  of  the  fused  metal  will  be  reduced  by  the  greater 
protection  from  atmospheric  oxygen  afforded  by  the  envelop- 
ing inert  gases.  With  increase  in  arc  length,  the  flame  becomes 
harder  to  control,  so  that  it  is  impossible  to  adequately  protect 
the  deposited  metal  from  oxidation. 

The  arc  length  should  be  uniform  and  just  as  short  as  it  is 
possible  for  a  good  welder  to  maintain  it.  Under  good  normal 
conditions  the  arc  length  is  such  that  the  arc  voltage  never 
exceeds  25  volts  and  the  best  results  are  obtained  between 
18  and  22  volts.  For  an  arc  of  175  amp.  the  actual  gap  will 
be  aboat  -J  inch. 

Manipulation  of  the  Arc. — The  arc  is  established  by  touch- 
ing the  electrode  to  the  work,  and  drawing  it  away  to  ap- 
proximately J  in.,  in  the  case  of  the  metallic  electrode.  This 


ARC   WELDING   PROCEDURE  83 

is  best  done  by  a  dragging  touch  with  the  electrode  slightly 
out  of  vertical.  The  electrode  is  then  held  approximately  at 
right  angles  to  the  surface  of  the  work,  as  the  tendency  is 
for  the  heat  to  go  straight  from  the  end  of  the  electrode.  This 
assures  the  fusing  of  the  work,  provided  the  proper  current 
and  arc  length  have  been  uniformly  maintained. 

A  slight  semicircular  motion  of  the  electrode,  which  at  the 
same  time  is  moved  along  the  groove,  will  tend  to  float  the 
slag  to  the  top  better  than  if  the  electrode  is  moved  along  a 
straight  line  in  one  continuous  direction  and  the  best  results 
are  obtained  when  the  welding  progresses  in  an  upward  direc- 
tion. It  is  necessary  in  making  a  good  weld  to  '  '  bite ' '  into 
the  work  to  create  a  perfect  fusion  along  the  edges  of  the 
weld,  while  the  movement  of  the  electrode  is  necessary  for  the 
removal  of  any  mechanical  impurities  that  may  be  deposited. 
It  is  the  practice  to  collect  the  slag  about  a  nucleus  by  this 


C 

FIG.  61. — Diagram  Illustrating  Filling  Sequence. 

rotary  movement  and  then  float  it  to  the  edge  of  the  weld. 
If  this  cannot  be  done,  the  slag  is  removed  by  chipping  or 
brushing  with  a  wire  brush. 

Filling  Sequence. — When  making  a  long  seam  between 
plates,  the  operator  is  always  confronted  with  the  problem 
of  expansion  and  contraction  which  cause  the  plates  to  warp 
and  produce  internal  strains  in  both  plates  and  deposited 
material. 

The  method  of  welding  two  plates  together  is  shown  in 
Fig.  61.  The  plates  are  prepared  for  welding  as  previously 
described,  and  the  arc  is  started  at  the  point  A.  The  welding 
then  progresses  to  the  point  B,  joining  the  edges  together,  to 
point  D  and  back  to  A.  This  procedure  is  carried  on  with 
the  first  layer  filling  in  a  space  of  6  or  8  in.  in  length,  after- 
ward returning  for  the  additional  layers  necessary  to  fill  the 
groove.  This  method  allows  the  entire  electrode  to  be  deposited 
without  breaking  the  arc,  and  the  thin  edges  of  the  work  are 


84 


ELECTRIC   WELDING 


not  fused  away  as  might  bo  the  case  if  the  operator  should 
endeavor  to  join  these  edges  by  moving  the  electrode  in-  one 
continuous  direction.  This  method  also  prevents  too  rapid 
chilling  with  consequent  local  strains  adjacent  to  the  weld. 

When  making  a  long  seam  weld,  for  example,  a  butt  weld 
between  two  plates,  the  two  pieces  of  metal  will  warp  and  have 
their  relative  positions  distorted  during  the  welding  process, 
unless  the  proper  method  is  used. 

A  method  was  devised  and  has  been  successfully  put  into 
operation  by  E.  Wanamaker  and  H.  R.  Pennington,  of  the 
Chicago,  Rock  Island  and  Pacific  R.R.  P>y  their  method  the 


FIG.  62. — Diagram  Illustrating  Back-Step  Method. 

plates  are  fastened  together  by  light  tack  welds  about  8  in. 
apart  along  the  whole  seam.  The  operator  then  makes  a  com- 
plete weld  between  the  first  two  tacks  as  described  in  the 
preceding  paragraph,  and,  skipping  three  spaces,  welds  between 
the  fifth  and  sixth  tacks  and  so  on  until  the  end  of  the  seam 
is  reached.  This  skipping  process  is  repeated  by  starting  be- 
tween the  second  and  third  tacks  and  so  on  until  the  complete 
seam  is  welded.  The  adoption  of  this  method  permits  the  heat, 
in  a  restricted  area,  to  be  dissipated  and  radiated  before  addi- 
tional welding  is  performed  near  that  area.  Thus  the  weld  is 
made  on  comparatively  cool  sections  of  the  plates  which  keeps 
the  expansion  at  a  minimum. 


ARC  WELDING  PROCEDURE  85 

Another  method  very  similar  to  the  preceding  one,  is  known 
as  the  back-step  method,  Fig.  62,  in  which  the  weld  is  performed 
in  sections  as  in  the  skipping  process.  After  the  pieces  are 
tacked  at  intervals  of  6  in.  or  less  for  short  seams,  the  arc 
is  applied  at  the  second  tack  and  the  groove  welded  back 
complete  to  the  first  tack.  Work  is  then  begun  at  the  third 
tack  and  the  weld  carried  back  to  the  second  tack,  practically 
completing  that  section.  Each  section  is  finished  before  start- 
ing the  next. 

Fig.  63  shows  the  procedure  of  welding  in  a  square  sheet 
or  patch.  Work  is  started  at  A  and  carried  to  B  completely 
welding  the  seam.  In  order  that  work  may  next  be  started 
at  the  coolest  point,  the  bottom  seam  is  completed  starting 
at  />,  finishing  at  C.  The  next  seam  is  A  to  D,  starting  at  A. 


D 

FIG.  63. — Diagram   Illustrating   Square   Patch   Method. 

The  last  seam  is  finished,  starting  at  5,  and  completing  the 
weld  at  C. 

Alternating- Current  Arc  Welding. — Direct  current  has  been 
used  for  arc  welding  because  of  the  fact  that  it  possesses  cer- 
tain inherent  advantages  that  make  it  especially  adaptable  for 
this  class  of  work.  However,  the  use  of  alternating  current 
for  arc  welding  has  found  a  number  of  advocates. 

When  employing  this  form  of  energy,  use  is  made  of  a  trans- 
former to  reduce  the  distribution  voltage  to  that  suitable  for 
application  to  the  weld. 

Inasmuch  as  the  arc  voltage  is  obtained  directly  from  the 
distribution  mains  through  a  transformer,  the  theoretical  effi- 
ciency is  high  compared  with  the  direct-current  process  which 
requires  the  introduction  of  a  motor- generator  or  resistor  or 


86  ELECTRIC  WELDING 

both.  The  efficiency  of  the  a.c.  equipments  now  on  the  market 
ranges  from  60  to  80  per  cent.  The  transformer,  however, 
is  designed  to  have  a  large  leakage  reactance  so  as  to  furnish 
stability  to  the  arc,  which  very  materially  reduces  its  efficiency 
when  compared  with  that  of  the  standard  distribution  trans- 
former used  by  lighting  companies. 

It  is  difficult  to  maintain  the  alternating  arc  when  using 
a  bare  electrode  though  this  difficulty  ic  somewhat  relieved 
when  use  is  made  of  a  coated  electrode. 

Quasi  Arc  Welding. — The  electrodes  used  in  quasi  arc  weld- 
ing are  made  by  the  Quasi  Arc  Weldtrode  Co.,  Brooklyn,  N. 
Y.,  and  are  known  as  "weldtrodes."  A  mild-steel  wire  is  used 
with  a  very  small  aluminum  wire  running  lengthwise  of  it. 
Around  the  two  is  wrapped  asbestos  thread.  This  asbestos 
thread  is  held  on  by  dipping  the  combination  into  something 
similar  to  waterglass.  Either  a.c.  or  d.c.  may  be  used,  at  a 
pressure  of  about  105  volts,  with  a  suitable  resistance  for 
regulating  the  current.  The  company's  directions  and  claims 
for  this  process  are :  "The  bared  end  of  the  weldtrode,  held  in 
a  suitable  holder,  is  connected  to  one  pole  of  the  current  supply 
by  means  of  a  flexible  cable,  the  return  wire  being  connected 
to  the  work.  In  the  case  of  welding  small  articles,  the  work 
is  laid  on  an  iron  plate  or  bench  to  which  the  return  wire  is 
connected.  Electrical  contact  is  made  by  touching  the  work 
with  the  end  of  the  weldtrode  held  vertically,  thus  allowing 
current  to  pass  and  an  arc  to  form.  The  weldtrode,  still  kept 
in  contact  with  the  work,  is  then  dropped  to  an  angle,  and  a 
quasi-arc  will  be  formed  owing  to  the  fact  that  the  special 
covering  passes  into  the  igneous  state,  and  as  a  secondary 
conductor  maintains  electrical  connection  between  the  work 
and  the  metallic  core  of  the  weldtrode.  The  action  once  started, 
the  weldtrode  melts  at  a  uniform  rate  so  long  as  it  remains 
in  contact,  and  leaves  a  seam  of  metal  fused  into  the  work. 
The  covering  material  of  the  weldtrode,  acting  as  a  slag,  floats 
and  spreads  over  the  surface  of  the  weld  as  it  is  formed.  The 
fused  metal,  being  entirely  covered  by  the  slag,  is  protected 
from  oxidation.  TRe  slag  covering  is  readily  chipped  or 
brushed  off  when  the  weld  cools,  leaving  a  bright  clean  metallic 
surface.  In  welding  do  not  draw  the  weldtrode  along  the 
seam,  as  it  is  burning  away  all  the  time,  and  therefore  it  is 


ARC  WELDING   PROCEDURE 


87 


only  necessary  to  feed  it  down,  but  do  this  with  a  slightly 
lateral  movement,  so  as  to  spread  the  heat  and  deposited  metal 
equally  to  both  sides  of  the  joint.  Care  must  be  taken  to  keep 
feeding  down  at  the  same  rate  as  the  weldtrode  is  melting. 
On  no  account  draw  the  weldtrode  away  from  the  work  to 
make  a  continuous  arc  as  this  will  result  in  putting  down 
bad  metal.  The  aim  should  be  to  keep  the  point  of  the  weld- 


After 


After 


After 


After 


After 


Before 


After 


Before 


After 


After 


Before 


After  _____ 

After 

After 
TIG.  64. — Typical  Examples  of  Prepared  and  Finished  Work. 

=> 

trode  just  in  the  molten  slag  by  the  feel  of  the  covering  just 
rubbing  on  the  work.  By  closely  observing  the  operation,  the 
molten  metal  can  easily  be  distinguished  from  the  molten  slag, 
the  metal  being  dull  red  and  the  slag  very  bright  red." 

The  weldtrodes  are  supplied  ready  for  use  in  standard 
lengths  of  18  in.,  and  of  various  diameters,  according  to  the 
size  and  nature  of  the  work  for  which  they  are  required. 


88 


ELECTRIC  WELDING 


Typical  Examples  of  Arc  Welding. — The  examples  of  weld- 
ing shown  in  Figs.  64,  65  and  66  are  taken  from  the  manual 
issued  by  the  Wilson  Welder  and  Metals  Co.  They  will  be 
found  very  useful  as  a  guide  for  all  sorts  of  work.  Fig.  64 


Before 


After 


Before 


33 


After 


Before 


Before 


After 


After 


After 


W" 

• 


After 


After 


Before 


Before 


After 


After 


After 


FIG.  65. — Examples  of  Tube  Work. 


shows  miscellaneous  plate  or  sheet  jobs,  Fig.  65  shows  tube 
jobs,  while  Fig.  66  gives  examples  of  locomotive-frame  and 
boiler-tube  welding. 

As  a  basis  for  various  welding  calculations  the  following 
data  will   be   found   of  use:    On   straight-away   welding  the 


ARC   WELDING   PROCEDURE 


89 


ordinary  operator  with  helper  will  actually  weld  about  75  per 
cent  of  the  time. 

The  average  results  of  a  vast  amount  of  data  show  that  an 


Great  care  must  be  exercised  in  the  preparation  of 
the  frames  for  welding,  and  that  the  proper  heat  valu9 
and  we  I  din  a  metals  ~pe  employed  tor  the  different 
character  or  material  in  the  frames^  to  be  welded 


Before  p    ^  Before 
Welding    1  Weld  ing 


After 
Welding 


•  •--)  U^^"*  J          ta*-  —  -^-^'  -     .     .  -j 

In  welding  flues  by  the  Electric  Arc  process,  the  flue  sheet  and  flues 


Pur  ruciy  t'C  vnrica  A'  inccr  cf/rrerenr  conairions.  ine  proper  heat  value 
to  emplcy  jnd  amount  of  me  fa/  to  apply  must  be  determined  in  each  case. 

FIG.  66. Examples  of  Electric  Welding  of  Locomotive  Frames  and 

Boiler  Tubes. 

operator 'can  deposit  about  1.8  Ib.  of  metal  per  hour.  This 
rate  depends  largely  upon  whether  the  work  is  done  out  in 
the  open  or  in  a  special  place  provided  in  the  shop.  For 
outside  work  such  as  on  boats,  an  operator  will  not  average 


90  ELECTRIC   WELDING 

in  general  more  than  1.2  Ib.  per  hour,  while  in  the  shop  the 
same  operator  could  easily  deposit  the  1.8  Ib.  stated  above. 
This  loss  in  speed  for  outside  work  is  brought  about  largely 
by  the  cooling  action  of  the  air  and  also  somewhat  by  the 
added  inconvenience  to  the  operator.  The  value  of  pounds 
per  hour  given  above  is  based  on  the  assumption  that  the  work 
has  been  lined  up  and  is  ready  for  welding.  On  the  average 
70  per  cent  of  the  weight  of  electrodes  is  deposited  in  the 
weld,  12  per  cent  is  burned  or  vaporized  and  the  remainder 
18  per  cent  is  wasted  as  short  ends. 

Other  figures  prepared  by  the  Electric  Welding  Committee 
show  the  possible  cost  of  a  fillet  weld  on  a  |-in.  plate,  using 
a  motor  generator  set  and  bare  electrodes  to  be  as  follows: 

Average  speed  of  welding  on  continuous  straight  away  work     5  ft.  per  hour 

Amount  of  metal  deposited  per  running  foot 6  Ib. 

Current  150  amps,  at  20  volts  =  3  kilowatts. 

Motor  generator  eff .  50  per  cent  =  6  kw.  -f-  5  equals     1.2  k.w.h.  per  1  ft.  run 

1.2  k.w.h.  at  3  cents  per  k.w.h.  equals 3.6  cents  per  ft. 

Cost  of  electrode  10  cents  per  pound  and  allowing 

for  waste  ends,  etc.,  equals 7.2  cents  per  ft. 

Labor  at  65  cents  per  hour  equals 13.00  cents  per  ft. 

23.8  cents  per  ft. 

Suggestions  for  the  Design  of  Welded  Joints. — From  an 
engineering  point  of  view,  every  metallic  joint  whether  it  be 
riveted,  bolted  or  welded,  is  designed  to  withstand  a  perfectly 
definite  kind  and  amount  of  stress.  An  example  of  this  is  the 
longitudinal  seam  in  the  shell  of  a  horizontal  fire-tube  riveted 
boiler.  This  joint  is  designed  for  tension  and  steam  tightness 
only  and  will  not  stand  even  a  small  amount  of  transverse 
bending  stress  without  failure  by  leaking.  If  a  joint  performs 
the  function  for  which  it  was  designed  and  no  more,  its  designer 
has  fulfilled  his  responsibilities  and  it  is  a  good  joint 
economically.  Regardless  of  how  the  joint  is  made  the  design 
of  joint  which  costs  the  least  to  make  and  which  at  the  same 
time  performs  the  functions  required  of  it,  with  a  reasonable 
factor  of  safety,  is  the  best  joint. 

The  limitations  of  the  several  kinds  of  mechanical  and 
welded  joints  should  be  thoroughly  understood. 

A  bolted  joint  is  expensive,  is  difficult  to  make  steam-  or 
water-pressure  tight,  but  has  the  distinguishing  advantage  that 


ARC  WELDING  PROCEDURE  91 

it  can  be  disassembled  without  destruction.  Bolted  joints  which 
are  as  strong  as  the  pieces  bolted  together  are  usually  imprac- 
ticable, owing  to  their  bulk. 

Riveted  joints  are  less  expensive  to  make  than  bolted  joints 
but  cannot  be  disassembled  without  destruction  to  the  rivets. 
A  riveted  joint,  subject  to  bending  stress  sufficient  to  produce 
appreciable  deformation,  will  not  remain  steam-  or  water- 
pressure  tight.  Riveted  joints  can  never  be  made  as  strong 
as  the  original  sections  because  of  the  metal  punched  out  to 
form  the  rivet  holes. 

There  is  no  elasticity  in  either  riveted,  bolted  or  fusion- 
welded  joints  which  must  remain  steam-  or  water-pressure 
tight.  Excess  -material  is  required  in  the  jointed  sections  of 
bolted  or  riveted  joints,  owing  to  the  weakness  of  the  joints. 

Fusion-welded  joints  have  as  a  limit  of  tensile  strength 
the  tensile  strength  of  cast  metal  of  a  composition  identical 
to  that  of  the  joined  pieces.  The  limit  of  the  allowable 
bending  stress  is  also  set  by  the  properties  of  cast  metal  of 
the  same  composition  as  that  of  the  joined  pieces.  The  reason 
for  this  limitation  is  that  on  the  margin  of  a  fusion  weld 
adjacent  to  the  pieces  joined,  the  metal  of  the  pieces  was  heated 
and  cooled  without  change  of  composition.  Whatever  proper- 
ties the  original  metal  had,  due  to  heat  or  mechanical  treatment, 
are  removed  by  this  action,  which  invariably  occurs  in  a  fusion 
weld.  Regardless  of  what  physical  properties  of  the  metal  used 
to  form  the  joint  may  be,  the  strength  or  ability  to  resist 
bending  of  the  joint,  as  a  whole,  cannot  exceed  the  correspond- 
ing properties  of  this  metal  in  the  margin  of  the  weld.  Thus, 
assuming  that  a  fusion  weld  be  made  in  boiler  plate,  having 
a  tensile  strength  of  62,000  pounds.  Assume  that  nickel-steel, 
having  a  tensile  strength  of  85,000  Ib.  be  used  to  build  up  the 
joint.  No  advantage  is  gained  by  the  excess  23,000  Ib.  tensile 
strength  of  the  nickel-steel  of  the  joint  since  the  joint  will 
fail  at  a  point  close  to  62,000  Ib.  If  appreciable  bending  stress 
be  applied  to  the  joint  it  will  fail  in  the  margin  referred  to. 

The  elastic  limit  of  the  built-in  metal  is  the  same  as  its 
ultimate  strength  for  all  practical  purposes,  but  the  ultimate 
strength  is  above  the  elastic  limit  of  the  joined  sections  in 
commercial  structures. 

In  spite  of  the  limitations  of  the  fusion-welded  joint  it  is 


92  ELECTRIC  WELDING 

possible  and  practicable  to  build  up  a  joint  in  commercial  steel 
which  will  successfully  resist  any  stress  which  will  be  en- 
countered in  commercial  work. 

The  fundamental  factor  in  the  strength  of  a  welded  joint 
is  the  strength  of  the  material  added  by  the  welding  process. 
This  factor  depends  upon  the  nature  of  the  stress  applied. 
The  metal  added  by  the  welding  process,  when  subject  to 
tension,  can  be  relied  on  in  commercial  practice  to  give  a  ten- 
sile strength  of  45,000  Ib.  per  square  inch.  This  is  an  average 
condition;  assuming  that  the  metal  added  is  mild  steel  and 
that  the  operation  is  properly  done,  the  metal  will  have  ap- 
proximately the  same  strength  in  compression  as  in  tension. 
When  a  torsional  stress  is  applied  to  a  welded  joint '  the 
resultant  stress  is  produced  by  a  combination  of  bending,  ten- 
sion and  compression,  as  well  as  shear.  The  resistance  of  the 
metal  to  shear  may  be  figured  at  8/io  its  resistance  to  tensile 
stress.  The  metal  added  by  the  welding  process,  with  the 
present  development  in  the  art  of  welding,  will  stand  very 
little  bending  stress.  A  fusion-welded  joint  made  by  the  elec- 
tric-arc process  must  be  made  stiffer  than  the  adjacent  sections 
in  order  that  the  bending  stress  shall  not  come  in  the  joint. 
An  electric  weld,  when  properly  made,  will  be  steam-  and 
water-pressure  tight  so  long  as  bending  of  members  of  the 
structure  does  not  produce  failure  of  the  welded  joint. 

Little  is  known  at  the  present  time  in  regard  to  the  resist- 
ance of  an  electrically  welded  joint  to  dynamic  stress,  but 
there  is  reason  to  believe  that  the  resistance  to  this  kind  of 
stress  is  low.  However,  owing  to  the  fact  that  in  most  struc- 
tures there  is  an  opportunity  for  the  members  of  the  structure 
to  flex  and  reduce  the  strain  upon  the  weld,  this  inherent  weak- 
ness of  the  welded  joint  does  not  interfere  seriously  with  its 
usefulness. 

A  few  tests  have  been  made  of  high-frequency  alternating 
stresses  and  it  has  been  found  that  using  the  ordinary  wire 
electrode  the  welded  joint  fails  at  a  comparatively  small  num- 
ber of  alternations.  This  is  of  little  importance  in  most  struc- 
tures since  high-frequency  alternating  stress  Ms  not  often 
encountered. 

Stresses  in  Joints. — The  accompanying  cuts  show  a  number 
of  typical  joints  and  the  arrows  indicate  the  stresses  brought 


ARC   WELDING   PROCEDURE 


93 


FIG.  67. — Joints  Designed  to  Overcome  Certain  Stresses. 


94 


ELECTRIC  WELDING 


to  bear  on  them.  The  proper  way  to  weld  each  example  is 
plainly  shown. 

In  A,  Fig.  67,  it  will  be  noted  that  a  reinforcing  plate  is 
welded  to  the  joint  to  make  the  joint  sufficiently  stiff  to  throw 
the  bending  outside  the  weld. 

B  shows  a  joint  in  straight  tension.  Since  no  transverse 
stress  occurs  the  heavy  reinforcing  of  A  is  not  required.  Just 
enough  reinforcing  is  given  the  joint  to  make  up  for  the  defi- 
ciency in  tensile  strength  of  the  metal  of  the  weld. 

C  shows  another  method  of  building  up  a  joint  that  is  in 


FIG.  68. — Plate  and  Angle  Construction. 

straight  tension.  It  Should  be  noted  that  in  both  B  and  C 
as  much  reinforcing  is  placed  on  one  side  of  a  center  line 
through  the  plates  as  is  placed  on  the  other. 

The  original  form  of  lap  joint  such  as  is  used  in  riveting 
is  shown  at  D.  The  method  shown  for  welding  this  joint  is 
the  only  method  which  can  be  used.  It  cannot  be  recommended 
because  such  a  joint,  when  in  straight  tension,  tends  to  bring 
the  center  line  of  the  plate  into  coincidence  with  the  center 
line  of  the  stress.  In  so  doing  an  excessive  stress  is  placed  on 
the  welded  material. 

E  shows  the  construction  used  in  certain  large  tanks  where 


ARC  WELDING   PROCEDURE 


95 


a  flanged  head  is  backed  into  a  cylindrical  shell.  The  principal 
stress  to  be  resisted  by  the  welded  joint  is  that  tending  to 
push  the  head  out  of  the  shell.  The  welding  process  indicated 
in  the  figure  will  successfully  do  this.  Owing  to  the  friction 
between  the  weld  and  the  shell,  the  outer  weld  would  be  suffi- 
cient to  hold  the  weld  in  place  for  ordinary  pressure.  For 
higher  pressures  the  inside  weld  should  be  made  in  addition. 


FIG.  69. — Pipe  Heading  and  Firebox  Sheet  Work. 

F  and  G  show  another  method  of  welding  a  flanged  head 
to  the  cylindrical  shell.  These  methods  are  preferable  to  the 
method  indicated  in  E.  G  represents  the  recommended 
practice. 

Fig.  68  shows  a  plate  and  angle  structure  which  might 
be  used  in  ship  construction.  The  particular  feature  to  notice 
in  the  welding  practice  indicated,  is  that  the  vertical  plates 
do  not  reach  the  entire  distance  between  the  horizontal  plates. 


96  ELECTRIC   WELDING 

This  is  merely  a  method  of  eliminating  difficulties  in  welding 
the  plates  to  the  angle. 

A  in  Fig.  69  shows  a  method  of  welding  a  head  into  a 
cylindrical  pipe.  The  thickness  of  the  head  should  be  ap- 
proximately twice  the  thickness  of  the  wall  of  the  pipe.  The 
extra  thickness  plate  is  to  gain  sufficient  stiffness  in  the  head 
to  make  the  stress  on  the  welded  material  purely  shear.  The 
pressure  from  the  inside  tends  to  make  the  head  assume  a 
hemispherical  shape.  This  would  place  a  bending  stress  on 
the  welded  material  if  the  head  were  thin  enough  to  give  at 
the  proper  pressure. 

B  shows  a  method  of  welding  a  crack  in  a  fire-box  sheet. 
The  thin  plate  backing  introduced  at  the  weld  makes  the 
operation  very  much  easier  for  the  operator  and  produces  the 
reinforcing  of  the  water  side  of  the  fire-box  sheet  which  is 
most  desirable. 

INSPECTION    OF   METALLIC    ELECTRODE   ARC    WELDS 

Determining  the  character  of  welded  joints  is  of  prime 
importance,  says  0.  S.  Escholz,  and  the  lack  of  a  satisfactory 
method,  more  than  any  other  factor,  has  been  responsible  for 
the  hesitancy  among  engineers  of  the  extensive  adoption  of 
arc  welding.  To  overcome  this  prejudice  it  is  desirable  to 
shape  our  rapidly  accumulating  knowledge  of  operation  into 
an  acceptable  method  of  inspection. 

Manufactured  apparatus  is  practically  all  accepted  on  the 
basis  of  complying  with  a  process  specification  rigidly  enforced 
in  conjunction  with  the  successful  reaction  to  certain  tests 
applied  to  the  finished  product.  Riveting  impairs  the  strength 
of  the  joined  plates,  yet  with  a  proper  layout  an^d  intelligent 
inspection  the  completed  structure  possesses  certain  definite 
characteristics  which  do  not  require  further  verification.  The 
inspector  of  a  finished  concrete  structure  is  practically  help- 
less, and  the  weakest  sort  of  construction  "may  be  concealed 
by  a  sound  surface.  With  careful  supervision,  however,  the 
physical  properties  of  the  completed  structure  can  be  reliably 
gaged  to  the  extent  that  the  use  of  concrete  is  justified  even 
in  ship  construction.  With  this  in  view,  electric  arc  welding 
is  susceptible  to  even  better  control  than  obtain  in  either  of 
these  structural  operations. 


ARC  WELDING   PROCEDURE  97 

The  four  factors  which  determine  the  physical  character- 
istics of  the  metallic  electrode  arc  welds  are:  Fusion,  slag 
content,  porosity  and  crystal  structure. 

Some  of  the  other  important  methods  that  have  been  sug- 
gested and  used  for  indicating  these  characteristics  are: 

1.  Examination  of  the  weld  by  visual  means  to  determine 
(a)   finish  of  the  surface  as  an  index  to  workmanship;    (b) 
length  of  deposits,  which  indicates  the  frequency  of  breaking 
arc,  and  therefore  the  ability  to  control  the  arc;  (c)  uniformity 
of  the  deposits,  as  an  indication  of  the  faithfulness  with  which 
the  filler  metal  is  placed  in  position;   (d)  fusion  of  deposited 
metal   to   bottom   of  weld   scarf   as   shown   by   appearance   of 
under   side    of   welded   joint;    (e)    predominance    of   surface 
porosity  and  slag. 

2.  The  edges  of  the  deposited  layers  chipped  with  a  cold 
chisel  or  calking  tool  to  determine  the  relative  adhesion  of 
deposit. 

3.  Penetration  tests  to  indicate  the  linked  unfused  zones, 
slag  pockets  and  porosity  by  (a)  X-ray  penetration;  (b)  rate 
of  gas  penetration;  (c)  rate  of  liquid  penetration. 

4.  Electrical  tests   (as  a  result  of  incomplete  fusion,  slag 
inclusions  and  porosity)   showing  variations  in  (a)   electrical 
conductivity;  (b)  magnetic  induction. 

These  tests  if  used  to  the  best  advantage  would  involve  their 
application  to  each  layer  of  deposited  metal  as  well  as  to  the 
finished  weld.  This,  except  in  unusual  instances,  would  not 
be  required  by  commercial  practice  in  which  a  prescribed 
welding  process  is  carried  out. 

Of  the  above  methods  the  visual  examination  is  of  more 
importance  than  generally  admitted.  Together  with  it  the 
chipping  and  calking  tests  are  particularly  useful,  the  latter 
test  serving  to  indicate  gross  neglect  by  the  operator  of  the 
cardinal  welding  principles,  due  to  the  fact  that  only  a  very 
poor  joint  will  respond  to  the  tests. 

The  most  reliable  indication  of  the  soundness  of  the  weld 
is  offered  by  the  penetration  tests.  Obviously  the  presence 
of  unfused  oxide  surfaces,  slag  deposits  and  blowholes  will 
offer  a  varying  degree  of  penetration.  Excellent  results  in 
the  testing  of  small  samples  are-  made  possible  by  the  use  of 
the  X-ray.  However,  due  to  the  nature  of  the  apparatus,  the 


98  ELECTRIC  WELDING 

amount  of  time  required  and  the  difficulty  of  manipulating 
and  interpreting  results,  it  can  hardly  be  considered  at  tlie 
present  time  as  a  successful  means  to  be  used  on  large-scale 
production. 

The  rate  that  hydrogen  or  air  leaks  through  a  joint  from 
pressure  above  atmospheric  to  atmospheric,  or  from  atmospheric 
to  partial  vacuum,  can  readily  be  determined  by  equipment 
that  would  be  quite  cumbersome,  and  the  slight  advantage 
over  liquid  penetration  in  time  reduction  is  not  of  sufficient 
importance  to  warrant  consideration  for  most  welds. 

Of  the  various  liquids  that  may  be  applied  kerosene  has 
marked  advantages  because  of  its  availability,  low  volatility 
and  high  surface  tension.  Due  to  the  latter  characteristics 
kerosene  sprayed  on  a  weld  surface  is  rapidly  drawn  into  any 
capillaries  produced  by  incomplete  fusion  between  deposited 
metal  and  weld  scarf,  or  between  succeeding  deposits,  slag 
inclusions,  gas  pockets,  etc.,  penetrating  through  the  weld  and 
showing  the  existence  of  an  unsatisfactory  structure  by  a  stain 
on  the  emerging  side.  A  bright-red  stain  can  be  produced  by 
dissolving  suitable  oil-soluble  dyes  in  the  kerosene.  By  this 
means  the  presence  of  faults  have  been  found  that  could  not 
be  detected  with  hydraulic  pressure  or  other  methods. 

By  the  kerosene  penetration  a  sequence  of  imperfect  struc- 
ture linked  through  the  weld,  which  presents  the  greatest 
hazard  in  welded  joints,  could  be  immediately  located,  but  it 
should  be  borne  in  mind  that  this  method  is  not  applicable 
to  the  detection  of  isolated  slag  or  gas  pockets  nor  small, 
disconnected  unfused  areas.  It  has  been  shown  by  various  tests, 
however,  that  a  weld  may  contain  a  considerable  amount  of 
distributed  small  imperfections,  without  affecting  to  a  great 
extent  its  characteristics. 

If  a  bad  fault  is  betrayed  by  the  kerosene  test  it  is  advis- 
able to  burn  out  the  metal  with  a  carbon  arc  before  rewelding 
under  proper  supervision.  By  the  means  of  sandblast,  steam 
or  gasoline  large  quantities  of  kerosene  are  preferably  removed. 
No  difficulty  has  been  encountered  on  welding  over  a  thin 
film  of  the  liquid. 

Electrical  tests,  by  which  the  homogeneity  of  welds  is 
determined,  are  still  in  the  evolutionary  stages,  and  many  diffi- 
culties are  yet  to  be  overcome  before  this  test  becomes  feasible. 


ARC  WELDING   PROCEDURE  99 

Some  of  these  difficulties  are  the  elimination  of  the  effect  of 
contact  differences,  the  influence  of  neighboring  paths  and 
fields,  and  the  lack  of  practicable,  portable  instruments  of  suffi- 
cient sensibility  for  the' detection  of  slight  variations  in  con- 
ductivity or  magnetic  field  intensity.  No  simple  tests  are 
plausible,  excepting  those  which  involve  subjecting  the  metal 
to  excessive  stresses  for  determining  the  crystal  structure. 
Control  of  this  phase  must  be  determined  by  the  experience 
obtained  from  following  a  prescribed  process. 

The  inspector  of  metallic  arc  electrode  welds  may  consider 
that  through  the  proper  use  of  visual,  chipping  and  penetrating 
tests .  a  more  definite  appraisal  of  the  finished  joint  may  be 
obtained  than  by  either  riveting  or  concrete  construction.  The 


r 


FIG.  70. — Typical  Arc- weld  Scarfs. 

operation  may  be  still  further  safeguarded  by  requiring  rigid 
adherence  to  a  specified  process. 

Good  results  are  assured  if  correct  procedure  is  followed. 

Haphazard  welding  can  no  sooner  produce  an  acceptable 
product  than  hit-or-miss  weaving  will  make  a  marketable  cloth. 
It  is  only  logical  that  all  the  steps  in  a  manufacturing  opera- 
lion  should  be  regulated  to  obtain  the  best  results.  As  it  is 
most  welders  consider  themselves  pioneers  in  an  unknown  art 
that  requires  the  exercise  of  a  peculiar  temperament  for  its 
successful  evolution,  and  as  a  result  welding  operators  enshroud 
themselves  in  the  halo  of  an  expert  and  do  their  work  with 
a  mystery  bewildering  to  the  untutored.  Once  in  a  while,  due 
we  might  say  to  coincidences,  these  " experts"  obtain  a  good 
weld,  but  more  often  the  good  weld  may  be  attributed  to  the 
friction  between  slightly  fused,  plastered  deposits. 

In  common  with  all  other  operations  metallic  electrode  aix», 


100  ELECTRIC   WELDING 

welding  is  really  susceptible  to  analysis.  Regardless  of  the 
metal  welded  with  the  arc  the  cardinal  steps  are:  (1)  Prepara- 
tion of  weld;  (2)  electrode  selection;  (3)  arc-current  adjust- 
ment; (4)  arc-length  maintenance,  and  (5)  heat  treatment. 

Sufficient  scarfing  is  involved  in  the  preparation  of  the 
weld,  as  well  as  the  separation  of  the  weld  slants,  so  that  the 
entire  surface  is  accessible  to  the  operator  with  a  minimum 
amount  of  filling  required.  When  necessary  to  avoid  distortion 
and  internal  stresses,  owing  to  unequal  expansion  and  contrac- 
tion strains,  the  metal  is  preheated  or  placed  so  as  to  permit 
the  necessary  movement  to  occur.  Various  types  of  scarfs  in 
common  use  are  shown  in  Fig.  70. 

The  electrode  selection  is  determined  by  the  mass,  thickness 


FIG.  71.— Good  and  Bad  Welds. 

and  constitution  of  the  material  to  be  welded.  An  electrode 
free  from  impurities  and  containing  about  17  per  cent,  carbon 
and  5  per  cent,  manganese  has  been  found  generally  satis- 
factory for  welding  low  and  high  carbon  as  well  as  alloy  steels. 
This  electrode  can  also  be  used  for  cast-iron  and  malleable-iron 
welding,  although  more  dependable  results,  having  a  higher 
degree  of  consistency  and  permitting  machining  of  welded 
sections,  can  be  obtained  by  brazing,  using  a  copper-aluminum- 
iron-alloy  electrode  and  some  simple  flux.  Successful  results 
are  obtained  by  brazing  copper  and  brass  with  this  electrode. 
The  diameter  of  the  electrode  should  be  chosen  with  reference 
to  the  arc  current  used. 

A  great  many  concerns  have  attempted  welding  with  too 


ARC   WELDING   PROCEDURE 


101 


low  an  arc  current  and  the  result  lias  been  a  poorly  fused 
deposit.    This  is  due  largely  to  the  overheating  characteristics 
of  most  electrode  holders,  or  using  current  value,  .and  thus- 
leading  the  operator  to  conclude  that  the  cufreril^iise'd  is  nV 
excess  of  the  amount  that  is  needed.  '^;^  :> 

A,  Fig.  71,  shows  a  section  through  one-half  of  air  exposed 
joint  welded  with  the  proper  current,  and  B  the  effects  of  too 
low  a  current.  The  homogeneity  and  the  good  fusion  of  the 
one  may  be  contrasted  with  the  porosity  and  poor  fusion  of 


ZOO 


Amperes  Arc  Current. 
FIG.  72.— Diameters  for  Welding  Steel  Plate. 


the  latter.  These  surfaces  have  been  etched  to  show  the  char- 
acter of  the  metal  and  the  welded  zone. 

The  approximate  values  of  arc  current  to  be  used  for  a 
given  thickness  of  mild-steel  plate,  as  well  as  the  electrode 
diameter  for  a  given  arc  current,  may  be  taken  from  the  curve 
in  Fig.  72.  The  variation  in  the  strength  of  1-in.  square  welded 
joints  as  the  welding  current  is  increased  is  shown  in  Fig.  73. 

Notwithstanding  that  the  electrode  development  is  still  in 
its  infancy  the  electrodes  available  are  giving  satisfactory 
results,  but  considerable  strides  can  yet  be  made  in  the  duc- 
tility of  welds,  consistency  in  results  and  ease  of  utilizing  the 
process. 

The  maintenance  of  a  short  arc  length  is  imperative.  A 
nonporous,  compact,  homogeneous,  fused  deposit  on  a  1-in. 


102 


ELECTRIC   WELDING 


square  bar  from  a  short  arc  is  shown  in  Fig.  74,  A,  and  in  B 

is  shown  a  porous,  diffused  deposit  from  a  long  arc.     Top 

.yiews  of*  these ,  welds  are  shown  in  Fig.  75.     A  short  arc  is 


SO  100  ISO 

Amperes  Arc  Current. 


zoo 


FIG.  73. — Variation  in  Weld  Strength  with  Change  in  Arc  Current. 


PIG.  74. — Sectional  Views  of  Short  and  Long  Arc  Deposits. 

usually  maintained  by  a  skillful  operator,  as  the  work  is  thereby 
expedited,  less  electrode  material  wasted  and  a  better  weld 
obtained  because  of  improved  fusion,  decreased  slag  content 


ARC   WELDING  PROCEDURE  103 

and  porosity.  On  observing  the  arc  current  and  arc  voltage 
by  meter  deflection  or  from  the  trace  of  recording  instruments, 
the  inspector  has  a  continuous  record  of  the  most  important 
factors  which  affect  weld  strength,  ductility,  fusion,  porosity, 
etc.  The  use  of  a  fixed  series  resistance  and  an  automatic 
time-lag  reset  switch  across  the  arc  to  definitely  fix  both  the 
arc  current  and  the  arc  voltage  places  these  important  factors 
entirely  beyond  the  control  of  the  welder  and  under  the  direc- 
tion of  the  more  competent  supervisor. 

Heat  Treatment  and  Inspection, — The  method  of  placing 
the  deposited  layers  plays  an  important  part  on  the  internal 
strains  and  distortion  obtained  on  contraction.  It  is  possible 
that  part  of  these  strains  could  be  relieved  by  preheating  and 


FIG.  75.— Top  Views  of  Welds  Shown  in  Fig.  74. 

annealing  as  well  as  by  the  allowance  made  in  preparation 
for  the  movement  of  the  metal. 

The  heat  treatment  of  a  completed  weld  is  not  a  necessity, 
particularly  if  it  has  been  preheated  for  preparation  and  then 
subjected  to  partial  annealing.  A  uniform  annealing  of  the 
structure  is  desirable,  even  in  the  welding  of  the  small  sections 
of  alloy  and  high-carbon  steels,  if  it  is  to  be  machined  or 
subjected  to  heavy  vibratory  stresses. 

The  inspector,  in  addition  to  applying  the  above  tests  to 
the  completed  joint  and  effectively  supervising  the  process, 
can  readily  assure  himself  of  the  competency  of  any  operator 
by  the  submission  of  sample  welds  to  ductility  and  tensile 
tests  or  by  simply  observing  the  surface  exposed  on  cutting 
through  the  fused  zone,  grinding  its  face  and  etching  with  a 
solution  of  1  part  concentrated  nitric  acid  in  10  parts  water. 

It  is  confidently  assumed,  in  view  of  the  many  resources 
at  the  disposal  of  the  welding  inspector,  that  this  method  of 


104  ELECTRIC   WELDING 

obtaining  joints  will  rapidly  attain  successful  recognition  as 
a  dependable  operation  to  be  used  in  structural  engineering. 

EFFECTS    OF    THE    CHEMICAL    COMPOSITION    OF    METALLIC    ARC 
WELDING    ELECTRODES 

In  order  to  ascertain  to  what  extent  the  chemical  analysis 
of  an  electrode  affected  the  welded  material  in  metallic  arc 
welding,  says  J.  S.  Orton,  two  electrodes  R  and  W  were  chosen 
of  widely  different  chemical  analyses,  each  0.148  in.  in  diameter. 
The  R  electrode  was  within  the  specifications  of  the  Welding 
Research  Committee  except  that  the  silicon  content  was  a  little 
high.  The  analyses  were  as  follows: 


R    wire 

C 

.     0  17 

Mn 
0  57 

P 

0  007 

S 
0  028 

Si 
0  14 

W  wire   

0.39 

1.01 

0.005 

0.024 

0  12 

The  silicon  content  was  rather  high,  but  inasmuch  as  it 
was  fairly  constant  in  both  electrodes  the  results  are  com- 
parative. 

A  deposit  was  made  on  a  |-in.  plate  by  means  of  a  metallic 
arc,  the  welded  section  being  approximately  1  ft.  long,  6  in. 
wide  and  1  in.  thick.  The  welding  machine  used  was  of  a 
well-known  make,  with  a  constant  voltage  of  37  volts  at  130 
amperes.  The  plates  used  for  depositing  the  first  layer  were 
machined  away  and  two  test  bars  were  made  from  each  elec- 
trode, composed  entirely  of  welded  material.  The  ends  were 
rough-machined  and  about  4^  in.  in  the  middle  of  the  specimens 
were  finished  carefully. 

The  physical  characteristics  of  the  plates  are  as  shown  in 
Table  V. 

TABLE  V. — PHYSICAL  CHARACTERISTICS  or  PLATES 


Tensile 
Strength 
57,300 

Elastic 
Limit 
43,400 

Elongation 
8.0 

KA 

Brinncl 
15  3 

2 

56  050 

50  500 

6  0 

5  9 

JF-1.    .  .    . 

76  200 

64000 

75 

13  0 

2  

72,650 

60,260 

5  5 

7  1 

After  these  bars  were  pulled,  chemical  analyses  were  taken 
at  various  points  to  get  the  values  given  in  Table  VI. 


ARC   WELDING   PROCEDURE 


105 


TABLE  VI. — CHEMICAL  ANALYSES  OF  SPECIMENS 


E-l 

C 
0.12 

Mn 
0.23 

P 
0.012 

s 

0.019 

Si 
0.10 

2  

0.09 

0.24 

0.016 

0.014 

0.08 

3 

0.11 

0.26 

0.014 

0.020 

0.08 

W-\ 

023 

0  84 

0.014 

0  012 

0  02 

o 

,  0.20 

0.80 

0.014 

0.014 

0.05 

3  

0.20 

0.88 

0.013 

0.013 

0.02 

Photographs  of  the  different  fractures  are  shown  in  Fig. 
77.  W-l,  which  gave  the  highest  tensile  strength,  shows  100 
per  cent,  metallic  structure  with  a  silky  appearance.  R-l 
shows  a  coarse  intergranular  fracture.  R-2  shows  a  brittle, 
shiny  crystalline  fracture  with  a  slag  inclusion  at  the  lower 
left-hand  and  upper  right-hand  corners  of  the  bars.  W-2 


FIG.  76. — Fractures  of  Test  Specimens. 

shows  partial  crystalline  and  partial  silky  fracture.  At  the 
extreme  right  there  is  a  portion  which  is  not  welded.  This 
is  probably  the  reason  why  W-2  did  not  pull  as  much  as  the 
other.  Undoubtedly,  next  to  the  chemical  analysis,  the  quan- 
tity of  slag  in  the  weld  has  the  biggest  bearing  on  the  tensile 
strength. 

The  structure  of  the  test  specimens  is  shown  in  the  micro- 
photographs  of  Fig.  77.  In  making  these  photographs,  no 
attempt  was  made  to  make  a  complete  microanalysis  of  the 
two  different  specimens,  but  rather  it  was  intended  to  show 
the  general  difference  in  structure  between  the  two  different 
types  of  electrode.  All  of  these  photographs  were  taken  at 
150  diameters  except  the  last  two,  which  were  taken  at  100. 

Photograph  R-1A  shows  the  general  structure  of  the  plate 
welded  with  the  R  electrode.  This  photograph  shows  a  large- 


106 


ELECTRIC  WELDING 


ARC  WELDING  PROCEDURE  107 

grain  growth  and  columnar  structure  which  are  characteristic 
of  electric  welds.  Photograph  Wl-A  shows  the  general  struc- 
ture of  the  plate  welded  with  the  W  electrode.  This  shows 
comparatively  small-grain  structure.  The  structure  seems  to 
be  much  better  than  that  of  Rl-A.  Photograph  Rl-B  shows 
a  portion  of  a  test  specimen  which  was  cut  out  of  plate  Rl 
and  bent  to  an  angle  of  10  deg.  It  is  interesting  to  note  here 
the  opening  up  of  the  welded  material  adjacent  to  slag  inclu- 
sions. Photograph  Wl-B  shows  a  portion  of  a  small  specimen 
cut  out  from  sample  Wl  and  bent  to  an  angle  of  10  deg.,  the 
same  as  in  the  case  of  Rl-B.  The  welded  material  is  opening 
up  but  not  in  the  same  degree  nor  around  the  slag  inclusions 
as  in  the  corresponding  photograph  Rl-B.  Photograph  Rl-C 
is  a  profile  of  the  fracture  of  the  Rl  sample  after  bending 
through  an  angle  of  15  deg.  Photograph  Wl-C  shows  the  Wl 
sample  after  being  bent  through  an  angle  of  17  degrees. 

It  seems  just  as  important  to  specify  the  chemical  composi- 
tion of  the  electrode  used  in  metallic  arc  welding  as  it  is  to 
specify  the  chemical  composition  in  ordering  any  other  type 
of  steel. 

Chemical  composition  seems  to  affect  the  physical  properties 
in  electrodes  as  well  as  other  steel. 

An  excess  of  manganese  seems  to  be  needed  in  electrodes. 

The  relation  between  the  carbon  and  manganese  of  an  elec- 
trode should  be  approximately  one  to  three. 

High-carbon  manganese  wire  tends  not  only  to  improve 
the  weld  on  account  of  the  amount  of  carbon  and  manganese 
in  the  welded  material,  but  also  on  account  of  the  type  of 
structure  which  this  wire  lends  to  the  deposited  metal. 

There  is  a  smaller  amount  of  oxide  and  slag  inclusions  with 
a  high-carbon  manganese  wire  than  with  a  comparatively  low- 
carbon  manganese  wire. 

WELDING    COMMITTEE   ELECTRODES 

After  an  exhaustive  series  of  tests  the  Welding  Committee 
drew  up  the  following  tentative  specification  for  electrodes 
intended  to  be  used  in  welding  mild  steel  of  shipbuilding 
quality : 

Chemical  Composition. — Carbon,  not  over  0.18  per  cent; 
manganese,  not  over  0.55  per  cent;  phosphorus,  not  over  0.05 


108  ELECTRIC   WELDING 

per  cent;  sulphur,   not  over  0.05  per  cent;  silicon,  not   over 
0.08  per  cent, 

Sizes :  Fraction  of  Inch  Lbs.  Per  Foot  Foot  Per  Lb.  Lbs.  Per  100  Ft. 

1/8  0.0416  24  4.16 

5/32  0.0651  15.35  6.51 

3/16  0.0937  10.66  9.37 

Allowable  tolerance  0.006  plus  or  minus. 

Material. — The  material  from  which  the  wire  is  manufac- 
tured shall  be  made  by  any  approved  process.  Material  made 
by  puddling  process  not  allowed. 

Physical  Properties. — Wire  to  be  of  uniform  homogeneous 
structure,  free  from  segregation,  oxides,  pipes,  seams,  etc.,  as 
proven  by  micro-photo  graphs.  This  wire  may  or  may  not  be 
covered. 

Workmanship  and  Finish. —  (a)  Electric  welding  wire  shall 
be  of  the  quality  and  finish  known  as  "Bright  Hard"  or  "Soft 
Finish."  "Black  Annealed"  or  "Bright  Annealed"  wire  shall 
not  be  supplied.  (6)  The  surface  shall  be  free  from  oil  or 
grease. 

Tests. — The  commercial  weldability  of  these  electrodes  shall 
be  determined  by  means  of  tests  by  an  experienced  operator, 
who  shall  demonstrate  that  the  wire  flows  smoothly  and  evenly 
through  the  arc  without  any  detrimental  phenomena. 


CHAPTER   VII 
ARC  WELDING  TERMS  AND  SYMBOLS 

In  order  to  aid  the  standardization  of  the  various  types 
of  joints  and  welding  operations  the  practice  recommended 
by  the  Welding  Committee  of  the  Emergency  Fleet  Corp.,  for 


FIG.  78. — Standard  Symbols  Eecommended  by  the  Welding  Committee  of 
the  Emergency  Fleet  Corporation. 


STRAP 


FIG.  79. 

ship  work,  is  given.  The  symbol  chart  is  shown  in  Fig.  78 
and  the  application  of  special  terms  and  symbols  is  individually 
shown  in  Figs.  79  to  112  inclusive. 

109 


110 


ELECTRIC  WELDING 


FIG.  79. — A  Strap  weld  is  one  in  which  the  seam  of  two  adjoin- 
ing plates  or  surfaces  is  reinforced  by  any  form  or  shape  to  add 
strength  and  stability  to  the  joint  or  plate.  In  this  form  of 
weld  the  seam  can  only  be  welded  from  the  side  of  the  work 
opposite  the  reinforcement,  and  the  reinforcement,  of  whatever 


BUTT 


Fie,  80. 

shape,  must  be  welded  from  the  side  of  the  work  to  which 
the  reinforcement  is  applied. 

FIG.  80. — A  Butt  weld  is  one  in  which  two  plates  or  surfaces 
are  brought  together  edge  to  edge  and  welded  along  the  seam 
thus  formed.  The  two  plates  when  so  welded  form  a  perfectly 


LAP 


FIG.  81. 

flat  plane  in  themselves,  excluding  the  possible  projection 
caused  by  other  individual  objects  as  frames,  straps,  stiffeners, 
etc.,  or  the  building  up  of  the  weld  proper. 

FIG.  81. — A  Lap  weld  is  one  in  which  the  edges  of  two 
planes  are  set  one  above  the  other  and  the  welding  material  so 
applied  as  to  bind  the  edge  of  one  plate  to  the  face  of  the 


ARC  WELDING  TERMS  AND  SYMBOLS 


111 


other  plate.     In  this  form  of  weld  the  seam  or  lap  forms  a 
raised  surface  along  its  entire  extent. 

FIG.  82. — A  Fillet  weld  is   one  in  which  some  fixture   or 
member  is  welded  to  the  face  of  the  plate,  by  welding  along 


FILLET 


FIG.  82. 

the  vertical  edge  of  the  fixture  or  member  (see  welds  shown 
and  marked  A ) .  The  welding  material  is  applied  in  the  corner 
thus  formed  and  finished  at  an  angle  of  forty-five  degrees  to 
the  plate. 

FIG.  83. — A  Plug  weld  is  one  used  to  connect  the  metals  by 


PLUG 


FIG.  83, 


welding  through  a  hole  in  either  one  plate  A  or  both  plates  B. 
Also  used  for  filling  through  a  bolt  hole  as  at  C,  or  for  added 
strength  when  fastening  fixtures  to  the  face  of  a  plate  by 
drilling  a  countersunk  hole  through  the  fixtures  and  applying 
the  welding  material  through  this  hole,  as  at  D,  thereby  fasten- 
ing the  fixture  to  the  plate  at  this  point. 


112 


ELECTRIC   WELDING 


FIG.  84. — A  Tee  weld  is  one  where  one  plate  is  welded 
vertically  to  another  as  in  the  case  of  the  edge  of  a  transverse 
bulkhead  A,  being  welded  against  the  shellplating  or  deck. 
This  is  a  weld  which  in  all  cases  requires  exceptional  care  and 
can  only  be  used  where  it  is  possible  to  work  from  both  sides 


FIG.  84. 

of  the  vertical  plate.  Also  used  for  welding  a  rod  in  a  vertical 
position  to  a  flat  surface,  as  the  rung  of  a  ladder  C,  or  a  plate 
welded  vertically  to  a  pipe  stanchion  B,  as  in  the  case  of  water 
closet  stalls. 

FIG.  85.— A  Single   "V"   is  applied  to  the  "edge  finish " 
of  a  plate  when  this  edge  is  beveled  from  both  sides  to  an 


SINGLE  "V 


FIG.  85. 

angle,  the  degrees  of  which  are  left  to  the  designer.  To  be 
used  when  the  "V"  side  of  the  plate  is  to  be  a  maximum 
"strength"  weld,  with  the  plate  setting  vertically  to  the  face 
of  adjoining  member,  and  only  when  the  electrode  can  be 
applied  from  both  sides  of  the  work. 


ARC   WELDING   TERMS  AND  SYMBOLS 


113 


FIG.  86.— Double  "V"  is  applied  to  the  "edge  finish "  of 
two  adjoining  plates  when  the  adjoining  edges  of  both  plates 


DOUBLE  "V 


SPACE 
ANY  THICKNESS  '/8' 


FlG.     86. 

beveled  from  both  sides  to  an  angle,  the  degrees  of  which  are 
left  to  the  designer.  To  be  used  when  the  two  plates  are  to 
be  "butted"  together  along  these  two  sides  for  a  maximum 


STRAIGHT 


SYMBOL 

z 


:  NOTES  BELOW 


FIG.  87. 


"strength"  weld.     Only  to  be  used  when  welding  can  be  per- 
formed from  both  sides  of  the  plate. 

FIG.  87. — Straight  is  applied  to  the  "edge  finish"  of  a  plate, 
when  this  edge  is  left  in  its  crude  or  sheared  state.     To  be 


SINGLE  BEVEL 


FIG.  88. 


used  only  where  maximum  strength  is  not  essential,  or  unless 
used  in  connection  Avith  strap,  stiffener  or  frame,  or  where 
it  is  impossible  to  otherwise  finish  the  edge.  Also  to  be  used 


114 


ELECTRIC   WELDING 


for  a  "strength"  weld,  when  edges  of  two  plates  set  vertically 
to  each  other — as  the  edge  of  a  box. 

FIG.  88.— Single  Bevel  is  applied  to  the  edge  finish  of  a 


DOUBLE  BEVEL 


FIG.    89. 


plate,  when  this  edge  is  beveled  from  one  side  only  to  an  angle, 
the  degrees  of  which  are  left  to  the  designer.  To  be  used 
for  "strength"  welding,  when  the  electrode  can  be  applied 


DECK  PLATING 


FlG.    90. 


from  one  side  of  the  plate  only,  or  where  it  is  impossible  to 
finish  the  adjoining  surface. 

FIG.  89. — Double  Bevel  is  applied  to  the  edge  finish  of  two 
adjoining  plates,  when  the  adjoining  edges  of  both  plates  are 


ARC   WELDING  TERMS  AND  SYMBOLS  115 

beveled  from  one  side  only  to  an  angle,  the  degrees  of  which 
are  left  to  the  designer.  To  be  used  where  maximum  strength 
is  required,  and  where  electrode  can  be  applied  from  one  side 
of  the  work  only. 

FIG.  90. — Flat  position  is  determined  when  the  welding 
material  is  applied  to  a  surface  on  the  same  plane  as  the  deck, 
allowing  the  electrode  to  be  held  in  an  upright  or  vertical 
position.  The  welding  surface  may  be  entirely  on  a  plane 
with  the  deck,  or  one  side  may  be  vertical  to  the  deck  and 
welded  to  an  adjoining  member  that  is  on  a  plane  with  the 
deck. 

Horizontal  position  is  determined  when  the  welding  material 
is  applied  to  a  seam  or  opening,  the  plane  of  which  is  vertical 
to  the  deck  and  the  line  of  weld  is  parallel  with  the  deck, 


TACK 


FIG.  91. 

allowing  the  electrode  to  be  held  in  an  inboard  or  outboard 
position. 

Vertical  position  is  determined  when  the  welding  material 
is  applied  to  a  surface  or  seam,  whose  line  extends  in  a  direc- 
tion from  one  deck  to  the  deck  above,  regardless  of  whether 
the  adjoining  members  are  on  a  single  plane  or  at  an  angle 
to  each  other.  In  this  position  of  weld,  the  electrode  would 
also  be  held  in  a  partially  horizontal  position  to  the  work. 

Overhead  position  is  determined  when  the  welding  material 
is  applied  from  the  under  side  of  any  member  whose  plane 
is  parallel  to  the  deck  and  necessitates  the  electrode  being 
held  in  a  downright  or  inverted  position. 

FIG.  91. — A  Tack  weld  is  applying  the  welding  in  small 
sections  to  hold  two  edges  together,  and  should  always  be 
specified  by  giving  the  space  from  center  to  center  to  weld 
and  the  length  of  the  weld  itself.  No  particular  "design  of 
weld"  is  necessary  of  consideration. 


116 


ELECTRIC   WELDING 


A  Tack  is  also  used  for  temporarily  holding  material  in 
place  that  is  to  be  solidly  welded,  until  the  proper  alinement 
and  position  is  obtained,  and  in  this  case  neither  the  length, 
space,  nor  design  of  weld  are  to  be,  specified. 

FIG.  92. — A  Caulking  weld  is  one  in  which  the  density  of 


CAULKING 


FIG.  92. 

the  crystalline  metal,  used  to  close  up  the  seam  or  opening, 
is  such  that  no  possible  leakage  is  visible  under  a  water,  oil 
or  air  pressure  of  25  Ibs.  per  square  inch.  The  ultimate  strength 
of  a  caulking  weld  is  not  of  material  importance — neither  is 
the  "design  of  weld"  of  this  kind  necessary  of  consideration. 
FIG.  93. — A  Strength  weld  is  one  in  which  the  sectional 


STRENGTH 


FIG.  93. 

area  of  the  welding  material  must  be  so  considered  that  its 
tensile  strength  and  elongation  per  square  inch  must  equal 
at  least  80  per  cent  of  the  ultimate  strength  per  square  inch 
of  the  surrounding  material.  (To  be  determined  and  specified 
by  the  designer.)  The  welding  material  can  be  applied  in 
any  number  of  layers  beyond  a  minimum  specified  by  the 
designer. 

The  density  of  the  crystalline  metals  is  not  of  vital  im- 


ARC   WELDING   TERMS  AND  SYMBOLS 


117 


portance.     In  this  form  of  weld,  the  " design  of  weld"  must 
be  specified  by  the  designer  and  followed  by  the  operator. 

JPIG>  94. — A  Composite  weld  is  one  in  which  both  the  strength 
and  density  are  of  the  most  vital  importance.  The  strength 
must  be  at  least  as  specified  for  a  " strength  weld,"  and  the 
density  must  meet  the  requirements  of  a  "caulking  weld" 


COMPOSITE 


FIG.  94. 

both  as  above  defined.  The  minimum  number  of  layers  of 
welding  material  must  always  be  specified  by  the  designer, 
but  the  welder  must  be  in  a  position  to  know  if  this  number 
must  be  increased  according  to  the  welder's  working  con- 
ditions. 

FIG.  95. — Reinforced  is  a  term  applied  to  a  weld  when  the 
top  layer  of  the  welding  material  is  built  up  above  the  plane 


REINFORCED 


FIG.  95. 

of  the  surrounding  material  as  at  A  or  B,  or  when  used  for 
a  corner  as  at  C.  The  top  of  final  layer  should  project  above 
a  plane  of  45  degrees  to  the  adjoining  material.  This  45  degree 
line  is  shown  " dotted"  in  C.  This  type  is  chiefly  used  in  a 
"strength"  or  "composite"  kind  of  weld  for  the  purpose  of 
obtaining  the  maximum  strength  efficiency,  and  should  be  speci- 
fied by  the  designer,  together  with  a  minimum  of  layers  of 
welding  material. 


118 


ELECTRIC   WELDING 


FIG.  96. — Flush  is  a  term  applied  'to  a  weld  when  the  top 
layer  is  finished  perfectly  flat  or  on  the  same  plane  as  on  the 
adjoining  material  as  shown  at  D  and  E  or  at  an  angle  of 
45  degrees  when  used  to  connect  two  surfaces  at  an  angle  to 
each  other  as  at  F.  This  type  of  weld  is  to  be  used  where  a 
maximum  tensile  strength  is  not  all  important  and  must  be 


FLUSH 


FIG.  96. 


specified  by  the  designer,  together  with  a  minimum  number 
of  layers  of  welding  material. 

FIG.  97. — Concave  is  a  term  applied  to  a. weld  when  the 
top  layer  finishes  below  the  plane  of  the  surrounding  material 
as  at  G,  or  beneath  a  plane  of  45  degrees  at  an  angular  con- 
nection as  at  H  and  J. 

To  be  used  as  a  weld  of  no  further  importance  than  filling 


DOTTED  LIVES  SHOW  THE  FLUSH  ! 


FIG.  97. 

in  a  seam  or  opening,  or  for  strictly  caulking  purposes,  when 
it  is  found  that  a  minimum  amount  of  welding  material  will 
suffice  to  sustain  a  specified  pound  square  inch  pressure  with- 
out leakage.  In  this  ''type  of  weld"  it  will  not  be  necessary 
for  the  designer  ordinarily  to  specify  the  number  of  layers 
of  material  owing  to  the  lack  of  structural  importance. 

COMBINATION    SYMBOLS 

FIG.  98  shows  a  strap  holding  two  plates  together,  setting 
vertically,  with  the  welding  material  applied  in  not  less  than 
three  layers  at  each  edge  of  the  strap,  as  well  as  between 
the  plates  with  a  reinforced,  composite  finish,  so  as  to  make 
the  welded  seams  absolutely  water,  air  or  oil  tight,  and  to 


ARC   WELDING  TERMS   AND  SYMBOLS 


119 


attain  the  maximum  tensile  strength.  The  edges  of  the  strap 
and  the  plates  are  left  in  a  natural  or  sheared  finish.  This  type 
of  welding  is  used  for  particular  work  where  maximum  strains 
are  to  be  sustained. 

FIG.  99  shows  a  strap  holding  two  plates  together  hori- 


STRAP  WELD,  REINFORCED, 
COMPOSITE  OF  THREE  LAYERS, 
VERTICAL,  STRAIGHT, 


ISP*:, 


PLATE 


ERTICAL  WELD 


STRAP 


w, 


PLATE 


FIG.  98. 

zontally,  welded  as  a  strength  member  with  a  minimum  of 
three  layers  and  a  flush  finish.  Inasmuch  as  the  strap  neces- 
sitates welding  of  the  plates  from  one  side  only,  both  edges 
of  the  plates  are  bevelled  to  an  angle,  the  degrees  of  which 
are  left  to  the  discretion  of  the  designer.  The  edges  of  the 

STRAP  WELD.  FLUSH, 
I83HOF)        STRENGTH  OF  3  LAYERS, 
HORIZONTAL,  FLAT  AND 
OVERHEAD.  DOUBLE  BEVEL 


Fie.  99. 

strap  are  left  in  a  natural  or  sheared  state,  and  the  maximum 
strength  is  attained  by  the  mode  of  applying  the  welding 
material,  and  through  the  sectional  area  per  square  inch  exceed- 
ing the  sectional  area  of  the  surrounding  material. 

FIG.  100  represents  two  plates  butted  together  and  welded 


120 


ELECTRIC  WELDING 


flat,  with  a  composite  weld  of  not  less  than  three  layers,  and 
a  reinforced  finish.  A  strap  is  attached  by  means  of  overhead 
tacking,  the  tacks  being  four  inches  long  and  spaced  eight 
inches  from  center  to  center.  In  this  case,  the  welding  of 
the  plates  of  maximum  strength  and  water,  air  or  oil  tight, 


STRAP,  TACK,  OVERHEAD. 
8'  CENTER  TO  CENTER 
4'  LONG,  BUTT,  REINFORCED 
COMPOSITE  OF  3  LAYERS, 
FLAT.  STRAIGHT. 


OVERHEAD  XVELD 


FIG.  100. 

but  the  tacking  is  either  for  the  purpose  of  holding  the  strap 
in  place  until  it  may  be  continuously  welded,  or  because 
strength  is  not  essential.  All  the  edges  are  left  in  their  natural 
or  sheared  state. 

FIG.  101  represents  a  butt  weld  between  two  plates  with 
the  welding  material  finished  concaved  and  applied  in  a  mini- 


BUTT  WELD.  CONCAVE. 
CAULKING  OF  2  LAYERS. 
FLAT.  STRAIGHT 


FIG.    101. 

mum  of  two  layers  to  take  the  place  of  caulking.  The  edges 
of  the  plates  are  left  in  a  natural  shear  cut  finish.  This  symbol 
will  be  quite  frequently  used  for  deck  plating  or  any  other 
place  where  strength  is  not  essential,  but  where  the  material 
must  be  water,  air  or  oil  tight. 

FIG.  102  is  used  where  the  edges  of  two  plates  are  vertically 


ARC   WELDING  TERMS   AND   SYMBOLS 


121 


butted  together  and  welded  as  a  strength  member.  The  edges 
of  adjoining  plates  are  finished  with  a  "double  vee"  and  the 
minimum  of  three  layers  of  welding  material  applied  from 
each  side,  finished  with  a  convex  surface,  thereby  making  the 
sectional  area  per  square  inch  of  the  weld  greater  than  that 


BUTT  WELD.  REINFORCED. 
STRENGTH  OF  3  LAYERS. 
VERTICAL,  DOUBLE  VEE. 


FIG.  102. 

of  the  plates.  This  is  a  conventional  symbol  for  shell  plating 
or  any  other  members  requiring  a  maximum  tensile  strength, 
where  the  welding  can  be  done  from  both  sides  of  the  work. 
FIG.  103  shows  two  plates  butted  together  in  a  flat  position 
where  the  welding  can  only  be  applied  from  the  top  surface. 
It  shows  a  weld  required  for  plating  where  both  strength  and 


93F 


BUTT  WELD.  FLUSH, 
COMPOSITE  OF  3  LAYERS. 
FLAT.  DOUBLE  BEVEL. 


Fie.  103. 

watertightness  are  to  be  considered.  The  welding  material 
is  applied  in  a  minimum  of  three  layers  and  finished  flush  with 
the  level  of  the  plates.  Both  edges  of  the  adjoining  plates 
are  beveled  to  an  angle,  the  degrees  of  which  are  left  to  the 
discretion  and  judgment  of  the  designer,  and  should  only  be 
used  when  it  is  impossible  to  weld  from  both  sides  of  the  work. 


122 


ELECTRIC   WELDING 


FIG.  104  shows  the  edges  of  two  plates  lapping  each  other 
with  the  welding  material  applied  in  not  less  than  two  layers 
at  each  edge,  with  a  concaved  caulking  finish,  so  applied,  as 
to  make  the  welded  seams  absolutely  water,  air  or  oil  tight. 


LAP  WELD.  CONCAVE. 
CAULKING  OF  2  LAYERS, 
OVERHEAD  AND  FLAT 
STRAIGHT 


OVERHEAD  WELD 


FIG.  104. 


The  edges  of  the  plates  themselves  are  left  in  a  natural  or 
shared  finish.  Conditions  of  this  kind  will  often  occur  around 
bulkhead  door  frames  where  maximum  strength  is  not  ab- 
solutely essential. 

FIG.  105  is  somewhat  exaggerated  as  regards  the  bending 


LAP  WELD,  REINFORCED. 
STRENGTH  OF  3  LAYERS 
AND  TACKING,  18'  CENTER 
TO  CENTER,  6§  LONG, 
VERTICAL,  STRAIGHT. 


'I 


FIG.  105. 

of  the  plates,  but  it  is  only  shown  this  way  to  fully  illustrate 
the  tack  and  continuous  weld.  It  shows  the  edges  of  the 
plates  lapped  with  one  edge  welded  with  a  continuous  weld 
of  a  minimum  of  three  layers  with  a  reinforced  finish  thereby 
giving  a  maximum  tensile  strength  to  the  weld,  and  the  other 


ARC  WELDING  TERMS   AND  SYMBOLS 


123 


edge  of  the  plate,  tack  welded.  The  tacks  are  six  inches  long 
with  a  space  of  12  inches  between  the  welds  or  18  inches  from 
center  to  center  of  welds.  In  both  cases,  the  edges  of  the 
plates  are  left  in  a  natural  or  sheared  state. 


PLUG  AND  LAP  WELD, 
STRENGTH  OF  3  LAYERS 
FLUSH.  FLAT,  OVERHEAD, 
HORIZONTAL. 


FLAT   WELD 


3   2    1 


FIG.  106. 

FIG.  106  shows  a  condition  exaggerated,  which  is  apt  to 
occur  in  side  plating  where  the  plates  were  held  in  position 
with  bolts  for  the  purpose  of  alinement  before  being  welded. 
The  edges  are  to  be  welded  with  a  minimum  of  three  layers 
of  welding  material  for  a  strength  weld  and  finished  flush, 


PLUG  AND  FILLET  WELD, 
REINFORCED,  STRENGTH  OF 
3  LAYERS,  FLAT,  SINGLE 
BEVEL  AND  STRAIGHT. 


FIG.    107. 

and  after  the  bolts  are  removed,  the  holes  thus  left  are  to  be 
filled  in  with  welding  material  in  a  manner  prescribed  for 
strength  welding.  The  edges  of  the  plates  are  to  be  left  in 
a  natural  or  sheared  state,  which  is  customary  in  most  cases 
of  lapped  welding. 


124 


ELECTRIC   WELDING 


PIG.  107  shows  a  pad  eye  attached  to  a  plate  by  means 
of  a  fillet  weld  along  the  edge  of  the  fixture,  and  further 
strengthened  by  plug  welds  in  two  countersunk  holes  drilled 
in  the  fixture.  The  welding  material  is  applied  in  a  flat 
position  for  a  strength  weld  with  a  minimum  of  three  layers 

FILLET  WELD.  REINFORCED. 
COMPOSITE  OF  3  LAYERS, 
FLAT.  VERTICAL  AND 
OVERHEAD.  STRAIGHT. 


PIG.  108. 

and  a  reinforced  finish.  The  edges  of  the  holes  are  beveled 
to  an  angle,  which  is  left  to  the  judgment  of  the  designer, 
but  the  edges  of  the  fixture  are  left  in  their  natural  state. 
This  method  is  used  in  fastening  fixtures,  clips  or  accessories 
that  would  be  subjected  to  an  excessive  strain  or  vibration 


FILLET  WELD,  FLUSH, 
STRENGTH  OF  3  LAYERS 
FLAT.  STRAIGHT. 


FlG.    109. 

FIG.  108  shows  a  fixture  attached  to  a  plate  by  means  of 
a  composite  weld  of  not  less  than  three  layers  with  a  reinforced 
finish.  The  fixture  being  placed  vertically,  necessitates  a  com- 
bination of  flat,  vertical  and  overhead  welding  in  the  course 
of  its  erection.  Although  a  fixture  of  this  kind  would  never 


ARC   WELDI'NG   TERMS   AND  SYMBOLS 


125 


be  required  to  be  watertight,  the  composite  symbol  is  given 
simply  as  a  possibility  of  a  combination. 

FIG.    109   represents   a  fixture   attached  to   a   plate   by  a 
strength  fillet  weld  of  not  less  than  three  layers,  finished  flush. 


TEE  WELD.  FLUSH. 
STRENGTH  OF  3  LAYERS. 
FLAT.  SINGLE  VEE. 


FIG.  110. 

The  edges  of  the  fixture  are  left  in  their  natural  state,  and 
the  welding  material  applied  in  the  corner  formed  by  the 
vertical  edge  of  the  fixture  in  contact  with  the  face  of  the  plate. 
FIG.  110  illustrates  the  edge  of  a  plate  welded  to  the  face 
of  another  plate,  as  in  the  case  of  the  bottom  of  a  transverse 

TEE  WELD.  REINFORCED. 
STRENGTH  OF  3  LAYERS. 
VERTICAL.  SINGLE  VEE. 


FIG.    111. 

bulkhead  being  welded  against  the  deck  plating.  To  obtain 
a  maximum  tensile  strength  at  the  joint,  the  edge  of  the  plate 
is  cut  to  "  single  vee"  and  welded  on  both  sides  with  a  strength 
weld  of  not  less  than  three  layers,  and  finished  flush.  This 
would  be  a  convenient  way  of  fastening  the  intercostals  to 


126 


ELECTRIC  WELDING 


the  keelsons.  In  this  particular  case,  the  welding  is  done  in 
a  flat  position. 

FIG.  Ill  shows  another  case  of  tec  weld  with  the  scam  set- 
ting in  a  vertical  position,  and  the  welding  material  applied 
from  both  sides  of  the  work.  The  edge  of  the  plate  is  finished 
with  a  "  single  vee"  and  a  minimum  of  three  layers  of  welding 
material  applied  from  each  side,  finished  with  a  convex  surface, 
thereby  making  the  sectional  area,  per  square  inch  of  the  weld, 
greater  than  that  of  the  plate,  allowing  for  a  maximum  tensile 
strength  in  the  weld. 

FIG.  112  represents  an  example  of  the  possible  combination 


STRAP  AND  TEE  WELD, 
FLAT,  REINFORCED,  TACK, 
12'  CENTER  TO  CENTER, 
6'  LONG,  SINGLE  BEVEL, 
OVERHEAD,  STRENGTH  OF 
3  LAYERS,  FLUSH 


FIG.    112. 

of  symbols.  An  angle  iron  is  tack  welded  to  the  plate  in  the 
form  of  a  strap  or  stiffener,  though  in  actual  practice,  this 
might  never  occur.  The  tacks  are  spaced  twelve  inches  from 
center  to  center,  and  are  six  inches  long,  and  applied  in  a 
flat  position,  with  a  reinforced  finish.  As  the  strap  prevents 
welding  the  plate  from  both  sides,  the  edge  of  the  plate  is 
beveled,  and  the  welding  material  applied  for  strength  in  not 
less  than  three  layers  in  an  overhead  position  and  finished 
flush.  Note  that  in  specifying  tack  welds,  it  is  essential  to 
give  the  space  from  center  to  center  of  weld,  and  length  of 
weld  by  use  of  figures  representing  inches  placed  either  side 
of  the  circumscribing  symbol  of  the  combination. 


CHAPTER    VIII 
EXAMPLES  OF  ARC-WELDING  JOBS 

Probably  no  mechanical  job  ever  attracted  more  general 
attention  than  the  repair  of  the  German  ships  seized  by  us 
when  we  entered  the  World  War.  Even  the  mechanically 
minded  Germans  repeatedly  declared  that  repairing  was  an 
impossibility,  but  the  American  engineers  and  mechanics 
showed  the  Hun  that  he  had,  as  usual,  vastly  over-rated  his 
own  knowledge.  One  big  factor  in  making  the  Hun  so  positive 
in  this  case,  was  his  utter  ignorance  regarding  the  possibilities 
of  arc  welding — but  he  learned  and  in  the  teaching  many 
others  were  also  enlightened. 

The  work  necessary  on  these  German  ships,  of  course,  in- 
cluded much  besides  welding  of  the  broken  castings,  but  the 
welding  work  was  of  primary  importance. 

The  principal  ships  on  which  this  welding  work  was  done 
were  the : 


Grqss 

Class  of 

U.  S.  Name 

German  name 

I.H.P. 

Tonnage 

Vessel 

Aeolus    

Grosser   Kurf  urst  

8,400 

13,102 

Transport 

Agamemnon  

Kaiser  Wilhelm  IT  .... 

45,000 

19,361 

Transport 

America  

America    

15,800 

22,621 

Transport 

Antigne   

Neckar   

5,500 

9,835 

Transport 

Covington    

Cincinnati    

10,900 

16,339 

Transport 

George  Washington. 

George  Washington  .... 

21,000 

25,570 

Transport 

Huron    

Friedrich   der   Grosse.  . 

6,800 

10,771 

Transport 

Leviathan    

Vaterland    

90,000 

54,282 

Transport 

Maclawaska    

Koenig  Wilhelm  II.... 

7,400 

9,410 

Transport 

Martha   Washington 

Martha   Washington  .  .  . 

6,940 

8,312 

Transport 

Mercury    

Barbarossa    

7,200 

10,984 

Transport 

Mt.   Vernon  

Kronprinzessin  Cecelie. 

45,000 

19,503 

Transport 

Pocahontas    

Prinzess   Irene  

9,000 

10,983 

Transport 

Powhatan    

Hamburg    

9,000 

10,893 

Transport 

President    Grant  .  .  . 

President  Grant  

8,500 

18,072 

Transport 

President  Lincoln.  . 

President   Lincoln  

8,500 

18,168 

Transport 

Savannah  

Saxonia   

2,500 

4.424 

Repair  Shop 

Susquehanna    

Ehein    

9,520 

10.058 

Transport 

Philippines    

Bulgaria    

4,200 

10,924 

Shipping  Bd. 

127 


128  ELECTRIC   WELDING 

The  total  gross  tonnage  of  the  ships  named  was  288,780 
tons,  and  the  welding  work  was  done  by  the  Wilson  Welder 
and  Metals  Co.  of  New  York,  using  their  "plastic-arc"  process. 

Seventy  Cylinders  Saved  Without  Replacement. — In  all, 
there  were  thirty-one  ships  interned  in  the  port  of  New  York. 
Of  these  thirty-one  ships,  twenty-seven  were  German  and  four 
Austrian.  Of  the  German  ships,  two  were  sailing  vessels  and 
four  were  small  steamers  which  the  Germans  had  not  taken 
pains  to  damage  materially.  This  left  twenty-one  German 
ships  whose  engines  and  auxiliaries  were  damaged  seriously, 
ranging  in  size  from  the  "Vaterland,"  the  pride  of  the  Ham- 
burg-American Line,  of  54,000  tons,  to  the  "Nassovia,"  of 
3,900  tons. 

On  the  cylinders  of  the  twenty  vessels  of  German  origin, 
not  counting  for  the  moment  the  turbine-driven  "Vaterland," 
there  were  no  less  than  118  major  breaks  which  would  have 
entailed  the  renewal  of  some  seventy  cylinders  if  ordinary 
practice  had  been  followed.  In  fact,  such  was  the  recommenda- 
tion of  the  surveying  engineers  in  their  original  report. 

To  any  engineer  familiar  with  the  conditions  at  that  time 
in  the  machine  shops  and  foundries  in  the  vicinity  of  New 
York,  also  in  the  drafting  rooms,  the  problem  of  producing 
seventy  cylinders  of  the  sizes  required  by  these  vessels  would 
seem  almost  impossible,  and  it  is  pretty  well  established  that 
some  vessels  would  have  had  to  wait  nearly  two  years  for 
this  equipment. 

It  must  be  remembered  that  few  drawings  of  these  engines 
were  available,  and  those  in  many  cases  were  not  discovered 
until  months  after  the  repairs  had  started.  Therefore,  it  would 
have  been  necessary  to  make  drawings  from  the  actual 
cylinders,  and  competent  marine  engine  draftsman  not  already 
flooded  with  work  did  not  exist. 

The  cylinders  of  fifteen  vessels  were  successfully  welded, 
while  those  of  six  were  repaired  by  fitting  mechanical  patches, 
or,  in  other  words,  eighty-two  of  the  major  breaks  were  repaired 
by  welding  and  thirty-six  by  mechanical  patches. 

It  was  not  until  July  12  that  the  final  decision  was  made 
placing  the  transport  service  in  the  hands  of  the  Navy  and 
designating  what  ships  were  to  be  transferred  from  the  control 
of  the  Shipping  Board  to  that  of  the  Navy  Department.  How- 


EXAMPLES  OF  ARC-WELDING  JOBS  129 

ever,  the  first  two  large  ships,  the  "Friedrich  der  Grosse," 
now  the  " Huron,"  and  the  "Prinzess  Irene,"  now  the  "Poca- 
hontas,"  were  ready  for  sea  on  Aug.  20,  in  spite  of  the  fact 
that  the  engines  on  these  vessels  were  among  the  worst  damaged 
of  them  all,  the  " Irene"  having  the  whole  side  of  the  first 
intermediate  valve  chest  broken  out  on  each  engine,  the  side 
of  the  high-pressure  cylinder  on  each  engine  destroyed,  and 
other  smaller  breaks,  which,  under  ordinary  methods,  would 
have  necessitated  the  renewal  of  four  cylinders.     The  "Fried-      ^ 
rich  der  Grosse ' '  had  the  following  breaks :  Broken  valve  chest      Z    2: 
of  high-pressure  cylinder  of  each  engine  (valve  chest  cast  in      Q    5 
one  with  the  cylinder),  flanges  knocked  off  both  valve  chest      t    § 
and  cylinder  covers,  steam  inlet  nozzles  knocked  off  both  first       ^      . 
intermediate  valve  chests  and  walls  between  the  two  valves       O    — 
in  each  check   broken  out,  also  steam   inlet  nozzles  on  both       U-    Jj 
second  intermediate  valve  chests  broken  off.  ^ 

These  two  vessels  were  the  first  in  which  straight  electric  £  O 
welding  was  used,  that  is,  where  patches  were  not  bolted  to  0)  \r 
the  cylinder  walls.  U  iu 

Method  of  Repair. — The  nature  of  some  of  the  breaks  in 
castings  is  shown  by  the  accompanying  photographs,  which        ?•    IE 
were  taken  at  various  stages  of  the  work. 

A,  Fig.  113,  shows  the  break  in  the  starboard  high-pressure 
cylinder  of  the  North  German  Lloyd  steamer  "  George  Wash- 
ington. ' '  This  break  was  effected  by  drilling  a  row  of  holes  about 
an  inch  apart  and  knocking  the  piece  out  with  a  ram. 

To  prepare  this  for  welding  it  was  necessary  to  chisel  off 
the  surface  only  roughly,  build  a  pattern  of  the  break,  cast 
a  steel  piece  from  the  pattern,  stud  up  the  surface  of  the  cast 
iron  of  the  cylinder  with  a  staggered  row  of  steel  studs  f  in.  in 
diameter,  projecting  |  in.  from  the  cylinder,  bevel  the  edge  of 
the  cast  piece,  place  the  piece  in  position  as  shown  in  B,  and 
make  the  weld.  When  completed,  the  appearance  of  the  work 
is  as  it  appears  in  C.  The  broad  belt  of  welded  metal  is  due 
to  the  laying  of  a  pad  of  metal  over  the  rows  of  studs  previously 
noted. 

It  cannot  be  too  strongly  insisted  that  tests  have  shown  con- 
clusively that  the  weld  can  be  properly  made  without  this  pad ; 
that  is,  if  the  approximate  strength  of  the  original  metal  is  all 
that  is  desired — in  which  case  the  studding  of  the  metal  is 


130 


ELECTRIC   WELDING 


a 


•a 


EXAMPLES  OF   ARC-WELDING  JOBS  131 

unnecessary.  But  the  work  in  these  particular  cases  was  of 
vital  importance,  due  to  the  uses  to  which  the  vessels  were 
to  be  put  when  in  service,  and  also  it  was  appreciated  that  this 
exhibition  of  a  new  application  of  the  art  in  the  marine  engineer- 
ing world  required  that  the  demonstration  be  satisfying,  not  only 
to  the  mind  of  the  engineer,  but  to  the  eye,  and  ear,  and  when 
any  engineer  looked  at  that  band  of  metal  and  sounded  it  with 
a  hammer,  he  could  not  be  but  satisfied  that  the  strength  was 
definitely  there  and  that  the  method  of  padding  could  be  used 
in  most  of  the  situations  which  would  arise.  This  at  least  was 
the  effect  upon  all  the  engineers  who  saw  the  actual  work. 

The  metal  was  laid  on  in  layers  in  such  a  manner  as  to 
take  care  of  the  contraction  in  cooling.  Each  successive  layer 
was  cleaned  with  a  wire  brush  before  the  next  layer  was  put 
on.  It  is  in  the  keeping  of  the  successive  layers  clean  and 
in  the  laying  on  of  the  metal  so  as  to  take  care  of  the  con- 
traction that  the  operator's  ability  comes  in  fully  as  much 
as  it  does  in  the  handling  of  the  apparatus.  The  'cylinders 
were  not  removed,  but  were  repaired  in  place.  Thus  the  work 
of  fitting  was  reduced  to  a  negligible  quantity,  and  the  refitting 
of  lagging  was  not  interfered  with  by  projections,  other  than 
the  f-in.  pad,  which  is  laid  over  the  studs  for  extra  strength. 
It  will  also  be  noted  that  these  repairs  can  be  undertaken  at 
any  place  where  the  vessel  may  be  lying,  cither  at  her  loading 
dock  or  in  the  stream,  since  such  apparatus  may  be  carried 
on  barges,  which  can  be  placed  alongside  and  wires  run  to 
the  work. 

In  this  work  a  part  consisted  of  the  caulking  of  the  surface 
of  the  welds  which  prevents  porosity  and  also  locates  any 
brittle  spots  or  places  where  poor  fusion  of  metal  has  been 
obtained.  This  permits  the  cutting  out  of  the  bad  places  and 
replacing  with  good  metal.  The  tool  used  was  an  air  caulking 
hammer  operated  at  110  Ib.  air  pressure. 

Strength  of  Cast-iron  Welds.— Capt.  E.  P.  Jessop,  U.  S.  N., 
personally  tested  many  welds  for  tensile  strength  in  which 
cast  iron  was  welded  to  cast  steel,  and  in  but  one  case  was 
there  a  failure  to  obtain  practically  the  original  strength.  This 
case  was  due  to  an  inexperienced  operator  burning  the  metal, 
and  was  easily  detected  as  an  inferior  weld  without  the  strength 
test  being  applied. 


132  ELECTRIC   WELDING 

Much  has  been  said  about  the  effect  of  the  heat  of  welding, 
upon  the  structure  or  strength  of  cast  iron,  and  in  this 
particular  instance  the  Navy  engineer  who  had  direct  charge 
of  this  work,  made  experiments  to  note  if  there  were  any 
deleterious  effects  on  the  iron  resulting  from  the  action  of 
the  weld  and  reported  as  follows: 

' '  Scleroscopic  investigation  of  the  structure  of  the  welds  shows  only 
a  very  slight  vein  of  hard  cast  iron  at  the  line  of  the  weld,  shot  through 
with  fingers  of  gray  cast  iron,  while  behind  this  area  there  was  no  heat 
effect  whatever.  The  metal  thus  deposited  was  easily  workable  with  ham- 
mer and  chisel,  file  or  cutting  tool.  Another  very  important  feature  is 
that  with  the  use  of  the  low  voltage  and  absolute  automatic  current  control 
of  the  Wilson  system,  there  is  a  minimum  of  heat  transmitted  to  the  parts 
to  be  welded,  this  being  practically  limited  to  a  heat  value  absolutely 
necessary  to  bring  the  electrode  and  the  face  of  the  metal  to  be  welded 
into  a  semi-plastic  state,  thus  insuring  a  perfect  physical  union,  and  in 
accomplishing  this  result  neither  of  the  metals  suffers  from  excessive  heat, 
and  there  is  absolutely  no  necessity  for  pre-heating.  Neither  are  there 
any  adverse  results  from  shrinkage  following  the  completed  work  owing 
to  a  minimum  amount  of  heat  being  transmitted  to  the  repair  parts,  thus 
avoiding  the  possibility  of  distortion  of  parts  through  uneven  or  excessive 
shrinkage  strains  that  are  very  common  where  pre-heating  is  necessary  or 
excessive  heat  is  used  for  fusing  metals." 

A,  Fig.  114,  shows  the  damage  done  to  the  first  intermediate 
cylinder  of  the  U.  S.  S.  '  *  Pocahontas, "  formerly  the  "Prinzess 
Irene. "  The  damage  to  this  cylinder,  it  will  be  noted,  was  more 
destructive  than  to  that  of  the  ' '  George  Washington, ' '  rendering 
the  repairs  much  more  difficult. 

B  shows  the  steel  section  in  place  ready  for  welding,  with 
the  surfaces  properly  V'd  out  and  with  a  staggering  row  of 
steel  studs  adjacent  to  the  welding  edge  of  the  cylinder  section. 

C  shows  the  complete  job  with  the  extra  band  or  pad  of 
metal  completely  covering  the  studs  on  the  cast-iron  section. 
These  bands  or  pads  of  metal  are  peaned  or  worked  over  with 
a  pneumatic  hammer  to  insure  protection  against  porosity  of 
metal. 

Had  either  or  both  of  these  cylinders  been  fractured  on  the 
lines  shown  of  the  cast-iron  sections,  and  none  of  the  parts 
removed,  then  the  surfaces  or  edges  of  all  lines  of  fracture 
would  have  been  V'd  out,  and  the  weld  made  of  the  two  cast- 
iron  surfaces  in  the  same  manner  that  the  cast  steel  was  welded 
to  the  cast-iron  cylinder  proper. 


EXAMPLES  OF  ARC-WELDING  JOBS 


133 


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134  ELECTRIC  WELDING 

OTHER    SHIP    WORK 

In  line  with  the  foregoing  J.  0.  Smith,  writing  in  the 
American  Machinist,  Jan.  22,  1920,  says:  When  the  matter  of 
welding  in  connection  with  ship-construction  is  considered,  im- 
mense possibilities  immediately  suggest  themselves.  It  has 
been  definitely  determined  by  exhaustive  technical  study  and 
experiment  that  welding  can  be  satisfactorily  employed  in 
ship  construction,  that  ship  plates  joined  by  welding  will  be  as 
strong  or  stronger  than  the  original  metal  at  the  welded  joint, 
and  that  welding  can  be  employed  for  ship-construction  work 
at  a  saving  of  25  per  cent,  in  time  and  10  per  cent,  in  material, 
as  compared  to  riveting. 

In  actual  figures,  as  determined  by  experiments  of  the 
Emergency  Fleet  Corporation's  electric  welding  committee,  it 
was  determined  that,  by  welding,  in  the  case  of  a  9500-ton 
ship  the  saving  in  rivets  and  overlapped  plates  would  amount 
in  weight  to  500  tons,  making  it  possible  for  the  ship  to  carry 
500  tons  more  cargo  on  each  trip  than  would  be  possible  if 
the  ship  plates,  etc.,  had  been  riveted,  instead  of  welded. 

An  investigation  by  the  same  committee  has  definitely 
established  the  following  points:  That  electric-welded  ships 
can  be  built  at  least  as  strong  as  riveted  ships;  that  plans  for 
ships  designed  to  be  riveted  can  easily  be  modified  so  as  to 
adapt  them  for  extensive  electric  welding,  and  thus  save  con- 
siderably in  cost  and  time  for  hull  construction ;  that  ships 
especially  designed  for  electric  welding  can  be  built  at  a  saving 
of  25  per  cent,  over  present  methods  and  in  less  time. 

An  electrically  welded  ship  is  credited  with  many  ad- 
vantages over  a  riveted  ship.  In  a  5000-ton  ship,  about  450,000 
rivets  are  used.  A  9500-deadweight-ton  ship  requires  600,000 
or  700,000  rivets.  By  the  welding  process  the  saving  in  labor 
on  the  minor  parts  of  a  ship  is  reckoned  at  from  60  to  70 
per  cent,  on  the  hull,  plating  and  other  vital  parts ;  the  saving 
in  labor,  cost  and  time  of  construction  by  welding  is  conserva- 
tively placed  at  25  per  cent. 

That  electric  welding  will  some  day  largely  replace  riveting 
is  also  the  judgment  of  the  electric-welding  committee  which 
is  composed  of  many  leading  experts  in  both  the  electrical 
and  metallurgical  branches  of  the  welding  field. 


EXAMPLES  OF  ARC-WELDING   JOBS  135 

Considerable  investigation  of  the  subject  of  welding  instead 
of  riveting  has  been  made  in  England  by  Lloyd's  Register  of 
Shipping,  particularly  with  regard  to  formulating  rules  for 
application  to  the  electrical  welding  of  ships.  As  a  result  of 
the  investigations  and  experiments  made  by  the  technical  staff, 
it  was  determined  that  the  matter  had  assumed  such  importance 
as  to  warrant  the  formulation  of  provisional  rules  for  elec- 
trically welded  vessels,  and  these  have  been  issued,  for  the 
guidance  of  shipbuilders,  by  Lloyd's  Register. 

The  experiments  conducted  in  England  followed  three  well- 
defined  lines  of  investigation:  Determination  of  ultimate 
strength  of  welded  joints,  together  with  their  ductile  proper- 
ties; capability  of  welded  joints  to  withstand  alternating  ten- 
sile and  compressive  stresses,  such  as  are  regularly  experienced 
by  ships;  and  a  microscopic  and  metallurgical  analysis  to 
determine  if  a  sound  fusion  was  effected  between  the  original 
and  added  metal. 

It  was  determined  that  the  tensile  strength  of  the  welded 
joints  was  from  90  to  95  per  cent,  of  the  original  plates,  as 
against  a  strength  of  from  65  to  70  per  cent,  in  riveted  joints, 
showing  a  margin  of  25  per  cent,  increased  strength  in  favor 
of  the  welded  joints. 

The  result  of  the  tests  of  the  elastic  properties  of  welded 
joints  determined  that  there  was  a  slight  difference  in  favor 
of  the  riveted  joint,  but  the  art  of  welding  has  made  such  great 
strides  recently  that  it  is  now  believed  entirely  possible  to 
make  a  welded  joint  in  ship  plates  that  will  stand  as  great  a 
number  of  reversals  of  stresses  as  a  riveted  joint. 

Microscopic  and  metallurgical  analyses  have  determined 
that  a  good,  solid,  mechanically  sound  weld  was  made  between 
the  original  and  the  added  metal,  the  two  having  been  fused 
together  so  perfectly  that  no  line  of  demarcation  could  be  seen. 

The  rules  so  far  promulgated  by  Lloyd's  (January,  1920), 
have  been  necessarily  of  a  tentative  nature  and  will  no  doubt 
be  modified  and  enlarged  from  time  to  time  in  view  of  the 
experience  that  will  be  gained  after  welded  ships  have  been 
in  service  for  a  time. 

It  does  not  require  a  great  deal  of  imagination,  however, 
to  enable  anyone  to  form  the  opinion  that  the  shipbuilding 
industry  is  on  the  eve  of  great  modifications  in  constructional 


136  ELECTRIC   WELDING 

lines,  and  the  guidance  given  by  the  tests  and  comparisons 
so  far  made  will  undoubtedly  lead  to  important,  radical  de- 
partures and  developments. 

In  addition  to  the  increased  cost  of  riveting  as  compared 
to  welding,  it  is  practically  always  true  that  there  is  a  certain 
percentage  of  imperfectly  fitted  rivets,  that  do  nothing  more 
than  add  weight  to  the  ship.  The  main  purpose  of  a  rivet, 
of  course,  is  to  bind  two  or  more  thicknesses  of  material  to- 
gether, but?  if  the  rivet  is  bent,  loses  part  of  its  head  in  the 
riveting  process  or  otherwise  fails  in  its  proper  purpose,  there 
is  no  method  by  which  such  faults  can  be  corrected  after  the 
rivet  cools.  If  the  importance  of  the  riveted  part  requires 
a  perfect  joint,  the  faulty  rivets  must  be  removed  entirely, 
and  this  is  frequently  a  time-killing,  expensive  course  to  fol- 
low. When  it  is  considered  that  a  5500-ton  ship  requires 
approximately  450,000  rivets  to  bind  the  various  parts  and 
plates  and  also  that  a  certain  percentage  of  these  rivets  is 
not  fulfilling  the  purpose  for  which  they  were  put  into  the 
ship,  it  is  quite  evident  that  practically  every  ship  is  burdened 
with  a  good-sized  load  of  dead,  useless  weight.  Such  defective 
rivets  are,  in  fact,  more  than  a  useless  weight,  in  that  they 
are  a  menace  to  the  ship,  for  while  they  have  been  built  into 
the  ship  for  a  purpose,  and  are  supposed  to  be  fulfilling  that 
purpose,  there  is  no  telling  how  much  the  ship  has  been  weak- 
ened structurally  by  their  failure. 

There  are  many  reasons  for  defective  t  rivets,  and  one  of 
the  greatest  of  them  is  the  inaccessibility  of  the  parts  to  be 
riveted  and  the  consequent  difficulty  on  the  part  of  the  riveter 
in  putting  the  rivets  properly  in  place.  Another  reason  is  that 
there  is  no  certainty  that  rivets  are  at  a  proper,  workable 
temperature;  in  consequence  of  which  if  they  are  too  cold, 
the  pneumatic  hammer  now  generally  used  in  riveting  is  unable 
to  round  off  the  end  of  the  rivet  properly,  so  as  to  insure  a 
proper  binding  together  of  the  plates  the  rivet  is  supposed 
to  hold. 

In  many  cases,  when  such  faulty  rivets  are  discovered,  the 
present-day  method  is  to  weld  such  defective  spots,  which 
immediately  brings  up  the  natural  question  as  to  why  the 
plates  should  not  be  welded  in  the  first  place. 

The  ability  of  a  welder,  using  a  direct-current,  low-voltage 


EXAMPLES  OF  ARC-WELDING  JOBS 


137 


arc    with    automatically    regulated    current    to    make    sound 
mechanical  welds  in  cramped,  confined  spaces,  on  overhead 


FIG.  115. — Welded  Parts  for   Ships. 

or  vertical  walls,  in  fact,  anywhere  a  man  and  a  wire  can  go, 
naturally  suggests  that  welding  ship  plates  together  should  be 
the  primary  operation  in  shipbuilding;  and  from  present  in- 


FIG.  116. — Welded  Fuel-Oil  Tanks. 


dicatlons  and  the  trend  of  current  events,  it  seems  more  than 
likely  that  this  will  be  the  outcome  in  the  near  future. 

Examples  of  various  ship  parts  welded  by  the  metallic  arc 


138  ELECTRIC   WELDING 

are  shown  in  Fig.  115.     In  Fig.  116    is  shown  a  welded  tank 
and  in  Fig.  117  a  welded  steel-plate,  4X7  ft.  condenser. 

Reason  for  Successful  Welds. — In  connection  with  the 
work  just  described,  the  Wilson  people  claim  that  their  success, 
and  the  uniformity  of  their  welds,  was  made  possible  because 
their  apparatus  enables  the  welder  to  control  his  heat  at  the 
point  of  application.  In  welding  there  is  a  critical  temperature 
at  which  steel  can  be  worked  to  give  the  greatest  tensile 
strength,  and  also  ductility  of  metal.  By  raising  the  heat 
15  or  20  amp.  above  this  critical  amperage  a  fracture  of  the 


FIG.  117. — Welded   Steel-Plate  Condenser.     No  Rivets  in  Its  Construction. 

Size  4  x  "  Ft. 

weld  will  show  segregation  of  carbon  and  slag  pockets,  which, 
of  course,  weakens  the  weld.  If  the  amperage  is  decreased 
from  the  critical  temperature,  a  fracture  of  the  weld  will  show 
that  the  metal  has  been  deposited  in  globules,  with  many  voids, 
which  proves  that  the  weld  has  been  made  with  insufficient 
heat.  This  shows,  they  claim,  that  with  a  fluctuating  amperage 
or  voltage,  it  is  impossible  to  obtain  uniformly  high-grade 
welds. 

In  addition  to  their  apparatus  they  use  special  electrodes 
for  various  jobs.  One  electrode  is  composed  of  a  homogeneous 
alloy  combined  with  such  excess  of  manganese  as  will  com- 
pensate for  losses  while  passing  through  the  electric  arc,  thus 


EXAMPLES  OF  ARC-WELDING  JOBS 


139 


insuring  a  substantial  amount  of  manganese  in  the  welded  joint 
which  is  essential  to  its  toughness.     They  also  claim  to  have 


Fie.  118. — Welded  Locomotive  Frame. 


FIG.  119 Built  Up  Pedestal  Jaw. 

a  manganese  copper  alloy  welding  metal  electrode  which  is 
composed  of  iron  homogeneously  combined  with  such  an  ex- 
cess of  manganese  and  copper  over  the  amount  lost  in  the 


140 


ELECTRIC  WELDING 


arc  as  will  insure  to  the  welded  joint  a  substantial  additional 
degree  of  toughness  and  ductility. 

Their  special  electrodes  run  in  grades,  corresponding  in 
sizes  to  the  gage  numbers  of  the  American  Steel  and  Wire 
Co.'s  table.  Grade  6  is  for  boiler  work;  grade  8  can  be 
machined ;  grade  9  is  for  engine  frames,  etc. ;  grade  17  is  for 
filling  castings  and  grade  20  is  for  bronze  alloys,  bells,  etc. 
The  tensile  strength  of  welds  made  with  these  electrodes  is 


FIG.  120. — At  Work  on  a  Locomotive  Frame. 

given  as  from  40,000  to  60,000  Ib.  The  wire  furnished  is  usually 
gage  9,  approximately  5/32  in.  in  diameter.  This  is  shipped 
in  coils  of  about  160  Ib.  No  fluxes  are  used  with  any  of  these 
electrodes. 

Locomotive  Work. — The  railroad  shops  of  the  United  States 
were  among  the  first  to  use  arc  welding  to  any  extent.  In 
fact,  without  the  great  amount  of  experimental  work  done  in 
railroad  shops,  the  use  of  the  arc  in  the  repair  of  the  damaged 
ships  by  welding  would  have  been  practically  impossible. 


EXAMPLES  OF  ARC-WELDING  JOBS 


141 


In  some  cases  of  locomotive  repair  there  is  a  big  question 
in  the  minds  of  engineers  as  to  whether  replacement  is  to  be 
insisted  upon  or  welding  allowed.  Rules  have  been  drafted 
by  a  number  of  railroad  associations,  but  at  present  no  uniform 
rules  covering  all  cases  are  in  existence.  However,  on  certain 


FIG.  121. — Welding  Cracked  Driving  Wheel  Spokes. 

classes  of  work  there  is  no  real  question  that  welding  is  the 
quicker  and  better  way. 

In  Fig.  118  is  shown  a  repair  on  a  steel  locomotive  frame, 
the  size  of  the  smaller  section  being  5X6  in.  The  broken  ends 
were  beveled  off  on  each  side  and  a  piece  of  steel  bar  was 
welded  in  between  the  ends,  thus  saving  considerable  time  and 
electrode  material. 


142 


ELECTRIC   WELDING 


Fig.  119  shows  how  the  worn  face  of  a  pedestal  jaw  was 
built  up  by  means  of  the  " plastic-arc"  process. 


FIG.  122. — Welding   Locomotive    Boiler    Tubes    to   Back    Sheet 


FlG.  123  .—Method  of  Welding  Boiler  Tubes  to  Sheet. 

Another  frame-welding  job  is  shown  in  Fig.  120.  The  weld 
was  3  in.  high,  4|  in.  wide  and  4  in.  deep.  One  man  finished 
the  job  with  a  Westinghouse  outfit  in  about  5  hours. 


EXAMPLES  OF  ARC-WELDING  JOBS  143 

Fig.  121  shows  the  welding  of  a  locomotive  cast-steel  drive 
wheel.  Four  spokes  were  cracked. 

Fig.  122  shows  the  welding  of  locomotive  boiler  tubes  to 
the  back  flue  sheet.  All  of  these  jobs  were  done  by  the  "plastic- 
arc"  process,  and  represent  a  very  small  portion  of  the  kinds 
of  jobs  that  may  be  done  in  a  railroad  shop. 

The  method  of  welding  flue  ends  to  the  sheets  as  suggested 
by  Westinghouse  is  shown  in  Fig.  123. 

II.  A.  Currie,  assistant  electrical  engineer,  New  York  Cen- 
tral R.R.,  writing  in  Railway  Age,  says: 

The  saving  in  our  locomotive  shop  since  electric  welding  was  installed 
can  hardly  be  calculated  and  the  additional  mileage  that  is  obtained  from 
locomotives  is  remarkable.  This  is  mainly  due  to  the  following: 

"A.  Greater  permanency  of  repairs. 

"B.  Shorter  periods  in  the  shop,   giving  additional  use   of  equipment. 

"C.  Existing  shop  facilities  permit  taking  care  of  a  larger  number  of 
locomotives  than  originally  expected.  Shop  congestion  relieved. 

"D.  The  use  of  worn  and  broken  parts  which  without  electric  welding 
would  be  thrown  in  the  scrap  pile. 

' '  E.  The  time  required  to  make  repairs  is  much  less  and  requires 
fewer  men. 

"  F.  A  smaller  quantity  of  spare  parts  carried  in  stock. 

"The  following  is  a  brief  description  of  some  of  the  work  done  on 
steam  locomotives: 

"Flue  and  Fire  Box  Welding. — The  most  important  results  are  obtained 
by  welding  the  boiler  tubes  to  the  back  flue  sheet.  The  average  mileage 
between  shopping  on  account  of  leaky  flues  on  passenger  locomotives  was 
100,000  miles.  This  has  been  raised  to  200,000  miles  with  individual 
records  of  275,000  miles.  For  freight  this  average  has  been  raised  from 
45,000  to  100,000  miles.  At  the  time  of  locomotive  shortage  this  effect 
was  of  inestimable  value. 

"Good  results  have  been  obtained  without  the  use  of  sandblast  to 
prepare  the  tubes  and  sheets.  The  engine  is  either  fired  or  an  acetylene 
torch  used  to  burn  off  the  oil,  after  which  the  metal  is  cleaned  off  with  a 
scraping  tool.  The  ferrules  are  of  course  well  seated  and  the  tubes  rolled 
back.  The  boiler  is  filled  wilh  water  in  order  to  cool  the  tubes,  which 
having  a  much  thinner  cross-section  than  the  sheets,  would  overheat  suffi- 
ciently to  spoil  the  weld  or  burn  the  tube.  The  metal  is  then  laid  on, 
beginning  at  the  bottom  of  the  bead  and  working  to  the  top.  Records 
show  that  the  time  to  weld  a  Pacific  type  locomotive  boiler  complete  is 
12  hours. 

' '  A  variety  of  repair  work  is  readily  accomplished  in  locomotive  fire- 
boxes such  as  the  welding  of  crown-sheet  patches,  side-sheet  cracks  and  the 
reinforcing  and  patching  of  mud  rings.  Smokebox  studs  are  also  welded  on. 

"Side  Frames,  Couplers  and  Wheels. — Cracked  main  members  of  side 


144  ELECTRIC   WELDING 

frames  are  restored  and  wearing  parts  built  up  and  reinforced.  Because 
of  accessibility  no  special  difficulties  are  encountered  in  this  work.  Formerly 
this  work  was  chiefly  done  with  oil  welding  and  some  acetylene  and  thermit 
work,  but  it  was  very  much  more  expensive  as  the  preparation  required 
considerable  effort  and  took  a  good  deal  of  time. 

"Fifty  per  cent  of  the  engines  passing  through  the  shops  have  worn 
and  broken  coupler  parts  and  pockets.  By  welding  an  average  saving  of 
about  $15  per  coupler  is  made.  It  costs  about  $30  in  material  and  labor 
to  replace  a  coupler  and  only  $4  to  repair  the  average  broken  coupler. 
The  scrap  value  is  about  $5. 

''Great  success  has  resulted  from  various  repairs  to  steel  wheels  and 
tires.  Flat  spots  have  been  built  up  without  removing  the  wheels  from 
the  locomotives,  thus  effecting  a  great  saving  in  time  and  money.  Building 
up  sharp  flanges  saves  about  f-in.  cut  off  the  tread,  which  when  followed 
through  means  about  $30  for  a  pair  of  wheels,  a  great  increase  in  tire 
life  and  reduction  in  shop  costs. 

"Cylinders. — The  most  interesting  feature  developed  by  arc  welding 
was  the  accomplishment  of  cast-iron  welding.  The  difficulty  in  welding 
cast  iron  was  that  while  the  hot  metal  would  weld  into  the  casting,  on 
cooling  the  strain  would  tear  the  welded  portion  away  from  the  rest 
of  the  casting.  Small  studding  was  tried  out  with  no  success.  Not  until 
wrought-iron  studs,  proportioned  to  the  sectional  strength  of  the  casting, 
were  used  did  any  satisfactory  welds  turn  out.  Studding  of  this  large 
size  was  looked  upon  with  distrust,  as  it  was  thought  that  the  only  weld 
was  to  the  studding.  This  naturally  meant  that  the  original  structure 
was  considerably  weakened  due  to  the  drilling.  This,  however,  was  not 
the  case.  The  large  studding  was  rigid  enough  to  hold  against  the  cooling 
strains  and  prevented  the  welds  in  the  casting  from  pulling  loose,  thus 
adding  the  strength  of  all  the  welded  portion  to  that  of  the  studs.  In 
most  cases  where  external  clearance  will  permit,  sufficient  reinforcing  can 
be  added  to  more  than  compensate  for  the  metal  removed  in  drilling  for 
the  studs. 

"Perhaps  more  skill  is  required  for  this  class  of  welding,  but  with  a 
properly  prepared  casting  success  is  certain.  A  concrete  case  of  the  economy 
effected  in  welding  a  badly  damaged  cylinder  on  a  Pacific  type  engine 
is  as  follows: 

WELDED    JOB 

Cost  of  welding  broken  cylinder,  labor  and  material $125.00 

Length  of  time  out  of  service,  5  days  at  $20  a  day 100.00 

Scrap  value  of  old  cylinder  (8,440  Ib.  at  2.09  Ib.) 177.00 

Total $402~00 

EEPLACED    CYLINDER 

Cost  of  new  cylinder  ready  for  locomotive $1,000.00 

Labor  charge  to  replace  it 150.00 

Locomotive  out  of  service  18  days  at  $20  a  day 360.00 

$1,510.00 

Less  cost  of  welding 402.00 

Total  saving ~$  1,108. 00 


EXAMPLES  OF  ARC-WELDING  JOBS  145 

"Some  twenty-five  locomotives  have  been  repaired  in  this  way  at  one 
shop  alone. 

"Many  axles  are  being  reclaimed  by  building  up  the  worn  parts. 
These  are  tender  and  truck  axles  which  are  worn  on  the  journals,  wheel 
fits  and  collars.  The  saving  is  about  $25  per  tender  axle  and  $20  for 
truck  axles. 

' '  The  range  of  parts  that  may  be  repaired  or  brought  back  to  standard 
size  by  welding  is  continually  expanding.  Wearing  surfaces  on  all  motion 
links  and  other  motion  work,  crosshead  guides,  piston-rod  crosshead  fits, 
valves  and  valve  seats,  air,  steam,  sand  and  other  pipes,  keys,  pins  and 
journal  boxes  have  all  been  successfully  welded. 

"A  large  saving  is  effected  in  welding  broken  parts  of  shop  tools  and 
machinery.  During  the  war  this  was  of  untold  value,  as  in  some  cases 
it  was  out  of  the  question  to  get  the  broken  parts  replaced. 

"Training  of  Operators. — The  training  of  arc  welders  is  most  important. 
Success  depends  solely  on  the  men  doing  the  work.  They  must  be  instructed 
in  the  use  of  the  arc,  the  type,  size  and  composition  of  the  electrode 
for  various  classes  of  work  and  the  characteristics  of  the  various  machines 
they  will  be  called  upon  to  use.  ,A  properly  equipped  school  for  teaching 
these  matters  would  be  a  valuable  adjunct  for  every  railroad.  Manufac- 
turers of  equipment  have  recognized  the  importance  of  proper  instruction 
and  have  equipped  schools  where  men  are  taught  free  of  charge. 

"Supervision. — Co-ordinate  with  the  actual  welding  is  intelligent  super- 
vision. The  scope  of  the  supervisors  should  include  preparation  of  the 
job  for  the  welder  and  general  oversight  of  the  equipment  in  the  shop. 

' '  Thus  the  duties  of  the  inspector  might  be  summarized  in  the  following 
points : 

"1.  To  see  that  the  work  is  properly  prepared  for  the  operator. 
"2.  The  machines  and  wiring  are  kept  in  good  condition. 
"3.  Proper  electrodes  are  used. 

"4.  To  inspect  the  welds  in  process  of  application,  and  when  finished. 
"5.  To  act  as  adviser  and  medium  of  interchange  of  welding  practices 
from  one  shop  to  another. 

"In  work  such  as  flue  welding  and  industrial  processes  which  repeat 
the  same  operation,  piece-work  rates  may  be  fixed.  For  varying  repair 
jobs  this  method  cannot  be  used  with  justice  either  to  the  operator  or 
the  job. 

"Bare  electrodes  are  used  almost  exclusively,  even  for  a.c.  welds. 
Whenever  a  new  lot  of  electrodes  is  received  it  is  good  practice  to  make 
up  test-piece  samples  and  subject  them  to  careful  tests  and  analysis. 

' '  The  sizes  of  electrodes  and  uses  to  which  they  are  put  are  shown 
in  the  table. 

Size  Type   of  Work 

YS    in.  Flue  welding. 

6/32  in-  For  all  repair  work,  broken  frames,  cylinders,  etc. 

Y«  in-  For  building   up  wearing  surfaces. 


146 


ELECTRIC   WELDING 


"General  Rules. — In  closing  it  will  be  well  to  point  out  a  few  general 
rules  required  to  obtain  satisfactory  welds. 

"1.  The  work  must  be  arranged  or  chipped  so  that  the  electrode  may 
be  held  approximately  perpendicular  to  the  plane  of  welding. 
When  this  cannot  be  accomplished  the  electrode  must  be  bent 
so  that  the  arc  will  be  drawn  from  the  point  and  not  the  side 
of  the  electrode.  For  cast  iron  the  studding  must  be  properly 
arranged  and  proportioned.  The  surfaces  to  be  welded  must  be 
thoroughly  clean  and  free  from  grease  and  grit. 

"2.  The  proper  electrode  and  current  value  must  be  selected  for  the 
work  to  be  done. 

"3.  The  arc  should  be  maintained  as  constant  as  possible. 

"4.  For  nearly  all  work  the  prepared  surface  should  be  evenly  welded 
over  and  then  the  new  surfaces  welded  together. 

"5.  Suitable  shields  or  helmets  must  be  used  with  proper  color  values 
for  the  lenses. 


FIG.  124.— Built  Up  Cupped  Rail  Ends. 

1 '  For  locomotive  work  a  good  operator  will  deposit  an  average  of 
1  to  1£  Ib.  of  electrode  per  hour.  The  limits  are  from  1  to  2  Ib.  High 
current  values  give  more  ductile  welds,  in  proportion  to  deposited  metal. 
For  locomotive  welding  the  great  advantage  of  the  arc  over  thermit,  oil 
or  acetylene  welding  is  that  preparation  at  the  weld  is  all  that  is  necessary. 
No  secondary  preparation  for  expansion  of  the  members  is  necessary.  This 
is  the  great  advantage  in  welding  side  frames." 

Considerable  welding  work  is  done  in  building  up  worn 
track  parts.  Fig.  124  shows  the  building  up  of  cupped  rail 
ends  and  Fig.  125  shows  manganese-steel  cross-over  points 
built  up  by  arc  welding.  Such  repairs  have  stood  long  and 
hard  service. 


EXAMPLES  OF  ARC-WELDING  JOBS 


147 


Other  Welding  Work.— In  the  steel  mills  a  great  deal  of 
welding  is  required  to  build  up  worn  roll  or  pinion  pods.  Fig. 
126  shows  a  welder  at  work  building  up  worn  pods  with  a 
carbon  arc  and  filler.  Fig.  127  shows  a  finished  job  with  the 


FIG.  125. — Built  Up  Manganese  Steel  Cross-Over  Points. 


FIG.  126. — Building  Up  Worn  Roll  Pods. 

worn  part  outlined  in  white.    The  cost  of  repairing  four  ends 
(two  pinions)  was  $170.     The  pinions  cost  $1,000  each. 

The  way  a  five-ton  roll  housing  Avas  repaired  is  shown  in 
Fig.  128.  In  this  case  a  heavy  steel  plate  was  bolted  over 
the  crack  and  welded  as  indicated.  It  might  have  been  all 


148 


ELECTRIC   WELDING 


FIG.  127. — Finish-Welded  Pinion  Pods. 


FIG.  128. — Kepaued  5-Ton  Koll  Housing. 


EXAMPLES  OF  ARC-WELDING  JOBS 


149 


FIG.  129. — Welded  Blowholes  and  Machined  Pulley. 


FiG.  130, — Method  of  Welding  Taps  Broken  Off  in  the  Hole. 


150  ELECTRIC   WELDING 

right  to  weld  direct,  but  in  this  case,  owing  to  the  heavy  duty 
required,  it  was  thought  best  to  play  safe  and  use  the  steel 
plate. 

Welded  blowholes  in  the  rim  of  a  large  pulley  are  shown 
at  the  left  in  Fig.  129.  At  the  right  the  pulley  is  shown  after 
machining. 

Broken  taps  may  be  removed  if  a  nut  is  welded  on  as 
shown  in  Fig.  130.  In  doing  work  of  this  kind,  the  arc  is 
struck  on  top  of  the  tap  and  kept  there  until  the  metal  is 
built  up  above  the  top  of  the  hole.  An  ordinary  nut  is  then 
laid  over  it  and  welded  fast.  If  the  arc  is  kept  on  the  tap 
the  metal  may  run  against  the  sides  of  the  hole  but  will  not 
adhere,  but  care  must  be  exercised  so  as  to  not  let  the  arc 
strike  the  sides  of  the  hole. 

ELECTRIC    CAR   EQUIPMENT    MAINTENANCE 

The  growing  possibilities  of  electric  welding  processes  in 
connection  with  the  maintenance  of  rolling  ctock  and  other 
railway  equipment  have  been  a  source  of  amazement  to  every 
electric  railway  man  who  has  come  into  contact  with  the  prac- 
tice, says  the  Electric  Railway  Journal.  This  began  with  the 
repair  of  broken  members  of  the  various  parts  of  electric  car 
equipment  and  has  led  to  its  use  in  a  still  larger  field,  which 
includes  the  building  up  of  worn  surfaces  of  steel  parts  which 
previously  would  have  been  headed  for  the  scrap  heap.  The 
accompanying  illustrations  show  some  parts  of  electric  car 
equipment  which  have  been  reclaimed  by  electric  welding  in 
the  shops  of  several  electric  railways.  This  work  was  begun 
at  a  time  when  it  was  very  difficult  to  obtain  railway  equip- 
ment parts  and  it  has  resulted  in  large  savings  and  has  enabled 
the  equipment  to  be  returned  to  service  so  quickly,  that  the 
work  is  being  extended  and  used  for  defective-part  repair 
which  previously  would  not  have  been  considered. 

The  United  Traction  Company,  Albany,  N.  Y.,  constructed 
a  special  concrete  building  for  its  electrical  repair  work  a  year 
ago.  A  separate  room  was  built  at  one  end  of  this  building  and 
arranged  particularly  for  electric  welding,  and  all  important 
details  were  incorporated  in  the  design  to  fit  this  room  for  the 
purpose  to  which  it  was  to  be  put.  The  building  is  a  concrete 
structure  throughout  and  the  floor  of  the  welding  room  is  also 


EXAMPLES  OF  ARC-WELDING  JOBS 


151 


of  concrete.  In  dimensions  this  room  is  about  10  ft.X30  ft.  and 
it  is  entirely  inclosed  and  separated  from  the  rest  of  the 
building. 

As  a  safety  precaution  no  one  is  allowed  to  enter  the  weld- 
ing room  while  work  is  in  progress.  Two  observation  windows 
are  provided  on  either  side  of  the  entrance  door,  in  which 
colored  glass  has  been  installed  as  a  protection  to  the  eyes  of 
the  observer.  Any  one  having  business  in  the  welding  room 


PIG.  131. — G.  E.  Portable  Arc  Welding  Outfit. 

can  see  when  welding  work  is  being  done  and  thus  avoid  the 
danger  of  any  harmful  effect  from  the  light  of  the  arc. 

The  equipment  at  present  in  use  in  the  welding  room  con- 
sists of  a  General  Electric  motor-generator  set  and  an  oxy-acety- 
lene  welding  outfit,  a  welding  table,  convenient  holders,  masks 
and  other  welding  equipment,  and  a  chain  hoist  which  travels 
on  an  I-beam  the  length  of  the  room  and  also  outside  the 
entrance  to  pick  up  heavy  work  and  facilitate  the  handling  of 
heavy  parts.  Since  the  installation  of  this  equipment  the 
General  Electric  Company  has  developed  a  self  regulating 
welding  generator  which  constitutes  a  part  of  its  single-operator 


152 


ELECTRIC   WELDING 


metallic  electric  arc  welding  equipment.  This  can  be  either 
stationary  or  portable  and  as  it  is  self-contained  it  makes  a 
very  desirable  combination.  The  generator  has  a  two-pole 
armature,  in  a  four-pole  frame,  with  commutating  poles,  and 
generates  sixty  volts,  open  circuit.  Bucking  the  shunt  field 
is  a  series  field,  with  taps  brought  out  for  different  welding 
currents.  As  current  flows  from  the  main  brushes  through 
the  series  field  windings  it  reduces  the  generator  voltage  to 


FIG.  132. — G.  E.  Generator  Direct  Connected  to  Motor,  with  Control 
Panel  and  Starter. 

the  proper  welding  value.    Figs.  131  and  132  show  two  types 
of  G.  E.  equipment. 

One  of  the  most  important  operations  and  one  which  shows 
far  reaching  economies  in  the  work  undertaken  by  the  United 
Traction  Company  is  the  building  up  of  worn  armature  shafts, 
as  shown  in  Figs.  133  and  134.  The  pinion  ends  of  the  shafts 
were  "chewed  up"  due  to  the  wear  of  the  keyways  for  the 
pinions.  The  defective  ends  of  the  shafts  which  were  to  be 
repaired  were  carefully  cleaned  of  all  oil  and  dirt  and  sufficient 
metal  was  welded  on  so  that  the  shafts  could  be  re-machined 


EXAMPLES  OF  ARC-WELDING  JOBS 


153 


and  re-threaded.  A  large  number  of  these  armatures  were  all 
right  except  for  the  damage  to  the  keyways,  so  that  they 
were  returned  to  service  as  soon  as  the  shafts  were  re-machined 


FlG.   133. — Worn   Armature  Shafts  Before  Welding. 


FIG.  134.— Armature  Shafts  After  Welding. 

and  fitted.  Others  had  damaged  coils  or  grounded  insulation 
and  where  it  was  necessary  to  re-wind  an  armature  this  was 
stripped  before  the  welding  operations  took  place.  For  weld- 


154 


ELECTRIC  WELDING 


ing  operations  of  this  character  where  a  large  amount  of  work 
is  to  be  done  which  is  similar  in  character  the  General  Electric 
Company  has  developed  an  automatic  welding  machine 
described  elsewhere.  Its  chief  advantage  lies  in  the  increase 


in  speed  which  is  possible  and  the  uniformity  of  welds  which 
results.  In  the  work  done  at  Albany  the  building  up  and 
re-machining  of  the  shafts  cost  from  $3  to  $4  each,  which  was 
only  about  one-tenth  of  the  cost  of  a  new  shaft.  As  local 


EXAMPLES  OF  ARC-WELDING  JOBS  155 

conditions  as  to  labor  costs  as  well  as  the  cost  of  energy  vary 
to  quite  an  extent  detailed  costs  for  the  various  operations 
are  not  included,  but  on  roads  which  are  performing  this  work 
and  which  have  actual  data  regarding  the  purchase  cost  of 
the  various  parts,  the  savings  which  result  offer  convincing 
proof  of  the  economies  which  can  be  effected  with  the  use  of 
electric  arc  welding. 

Fig.  135  shows  a  pile  of  motor  cases  in  the  yards  of  the 
United  Traction  Company.  Before  the  advent  of  the  welding 
equipment  many  of  these  motor  shells  were  intended  for  scrap 


FIG.  136. — Kepaired  Gear-Case  Suspension  Arm. 

due  to  various  breakages  and  excessively  worn  parts.  By  the 
use  of  the  welding  equipment  a  large  proportion  of  these  have 
already  been  reclaimed. 

The  method  employed  in  welding  broken  lugs  or  broken 
ends  of  motor  shells  consists  first  in  fitting  the  broken  parts 
together  and  lining  them  up  in  their  correct  position.  The 
pieces  are  then  welded  at  a  few  points  so  as  to  hold  the  broken 
parts  in  position  and,  where  necessary,  the  fracture  is  cut  out 
"V"  shape  to  provide  additional  space  for  the  welding  metal. 
Much  of  the  success  which  has  been  obtained  in  this  class  of 
work  at  Albany  is  attributed  to  the  use  of  studs  for  inter- 


156 


ELECTRIC  WELDING 


locking  the  metal  which  is  added  to  the  broken  parts.  Holes 
for  the  f-in.  studs  are  drilled  and  tapped  at  several  points 
adjacent  to  the  break  and  the  studs  are  so  inserted  as  to 
extend  above  the  motor  shell  to  about  the  same  height  as  the 
thickness  of  the  additional  metal  to  be  added.  The  deposited 


FIG.  137. — Broken  Cast-Iron  Motor  Slrell  and  Axle  Housings  Repaired  by 
Electric  Welding   (Case  Broken  in  Twelve  Pieces). 

metal  is  then  allowed  to  bridge  over  these  studs  in  welding 
and  so  obtains  additional  support  which  helps  to  strengthen 
the  weld.  In  the  illustration  Fig.  136  showing  repairs  made 
to  a  broken  gear-case  suspension  arm,  one  of  these  studs  can 
be  seen  projecting  from  the  casting. 


EXAMPLES  OF  ARC-WELDING  JOBS 


157 


As  an  example  of  what  can  be  accomplished,  in  repairing 
broken  shells,  the  illustration  Fig.  137  showing  a  welded  end 
of  a  motor  shell  alongside  a  lathe,  is  an  extreme  case.  This 
motor  shell  was  broken  in  twelve  pieces  and  from  the  illus- 
tration it  will  be  seen  that  nearly  the  entire  end  was  welded. 

Another  record  job  made  in  the  shop  of  the  United  Traction 
Company  was  the  welding  of  a  truck  bolster.  The  car,  under 
which  was  a  truck  with  a  broken  bolster,  was  brought  to  the 
shop  and  placed  on  a  track  adjacent  to  the  welding  room. 


FIG.  138.  FIG.  139. 

FIG.  138. — Wheel  Turned  Down  Ready  for  Welding.     Note 

Thinness  of  Flange. 
FIG.  139.— Flange  Built  Up  Ready  to  Be  Shaped  in  Wheel  Lathe. 

The  car  body  was  jacked  up  and  the  bolster  was  repaired 
in  approximately  eight  hours.  The  work  was  started  at  9 
o'clock  after  the  morning  rush  hour  and  the  car  was  ready 
for  service  again  at  5.15  P.M. 

In  addition  to  the  class  of  work  illustrated  as  being  done 
by  the  United  Traction  Company  other  interesting  work  is 
reported  from  various  electric  railways  showing  what  has  been 
accomplished.  The  Spokane  &  Inland  Empire  Railroad  has 
done  some  work  in  reclaiming  wheels  with  sharp  flanges. 
Three  views  are  given  to  illustrate  the  methods  used.  The 


158 


ELECTRIC  WELDING 


first  of  these,  Fig.  138,  shows  a  wheel  with  the  flange  turned 
down  ready  to  receive  new  metal.  The  second  Fig.  139  shows 
the  flange  with  a  new  layer  of  welded  metal.  The  third,  Fig. 
140,  shows  the  finished  wheel  after  it  has  been  machined.  After 
the  new  metal  has  been  added  the  flange  is  merely  shaped  up 
with  a  forming  tool.  It  is  left  quite  rough  in  some  cases,  but 
as  the  practice  has  always  been  to  put  on  new  brake  shoes 
when  the  wheels  are  repaired,  the  company  has  had  no  difficulty 
in  wearing  down  the  tread  to  a  smooth  contour. 

A  number  of  steam  railways  are  at  present  reclaiming  all 
of  their  cold  rolled  steel  wheels  which  are  slid  flat  or  have 


FIG.  140. — Finished  Wheel  Ready  for  Service. 

flaked-out  places,  as  well  as  those  with  sharp  flanges.  This 
operation  creates  quite  a  saving  in  itself  as  often  the  car  is 
merely  placed  over  the  drop  pit  and  the  work  can  then  be 
taken  care  of  with  the  car  fully  equipped.  By  this  method 
the  car  is  withheld  from  service  but  a  short  period.  In  the 
welding  of  sharp  flanges  it  is  not  contended  by  those  who  have 
had  extended  experience  that  the  metal  deposited  will  give 
the  life  of  the  parent  material,  but  they  agree  that  savings 
are  created  as  a  result  of  maintaining  the  car  in  service  until 
such  time  as  it  is  necessary  to  shop  it  for  major  repairs. 

Another  example  of  reclaiming  electric  car  equipment  is 
shown  in  the  repairs  to  gear  cases,  Fig.  141.     These  are  a 


EXAMPLES  OF  ARC-WELDING  JOBS 


159 


fair  sample  of  the  repairs  that  are  frequently  found  necessary. 
In  this  case  patches  are  made  of  No.  10  sheet  iron.  In  welding 
these  patches  on,  the  operator  first  determines  the  size  of  the 
patch  and  outlines  it  with  chalk  on  the  old  case.  He  then 
builds  up  a  layer  of  metal  just  outside  the  chalk  mark.  The 
patch  is  then  laid  on  and  welded  to  a  layer  of  metal.  In 
this  way  a  tight  and  secure  joint  is  made.  As  gear  cases  are 
frequently  covered  with  oil  when  they  are  brought  in  for 
repairs,  they  should  be  cleaned  off  as  much  as  possible.  In 
making  a  patch  that  requires  a  bend,  as  in  the  case  illustrated, 
the  operator  first  welds  the  patch  to  the  bottom  of  the  case, 
then  heats  the  patch  and  bends  it  into  shape. 

Split  Gears  Made  Solid. — Some  electric  railways  which  have 


FlG.  141. — Gear  Cases  with  Patches  Welded  On. 

split  gears  have  found  it  advisable  to  change  these  to  solid 
gears  by  welding  and  then  to  press  them  on  the  axles.  Fig. 
142  shows  a  gear  which  is  being  welded  in  this  manner  and 
Pig.  143  an  axle  which  has  been  built  up  so  as  to  increase 
the  gear  seat.  The  method  employed  in  welding  the  gears 
consists,  first,  of  cutting  a  "V"  along  the  joint  of  the  gear 
down  to  the  bolts  with  a  carbon  electrode.  The  operator  then 
builds  up  with  new  metal  and  welds  each  bolt  and  fills  up 
the  old  keyways.  This  bore  is  then  re-machined  and  a  new 
keyway  is  cut.  Broken  teeth  in  gears  are  also  easily  repaired 
by  welding. 

Another  use  of  welding  which  has  been  of  benefit  to  electric 
railways  is  in  the  maintenance  of  housings  for  the  bearings 
of  railway  motors.  Constant  vibration  and  heavy  jarring 


160 


ELECTRIC   WELDING 


causes  the  fit  in  the  motor  frame  to  become  badly  worn  and 
many  railways  have  used  shims  to  take  up  this  wear.  A  small 
layer  of  metal  deposited  by  the  electric  arc  and  then  machined 
to  the  desired  dimensions  provides  a  more  serviceable  job  than 


FIG.  142. 


FIG.  143. 


FIG.  142.— Welding  Split  Gear  to  Make  a  Solid  One. 
FIG.  143. — Axle  Enlarged  by  Welding. 

that  of  the  shims,  and  when  a  tight  fit  is  once  secured,  the 
wear  is  eliminated. 

The  filling  in  of  bolt  holes  in  various  parts  of  the  car 
equipment  is  another  use  which  is  showing  far-reaching  results. 
Heavy  duty  and  constant  vibration  cause  the  holes  to  become 
worn,  and  the  bolts  then  readily  become  loose  and  often  fall 


EXAMPLES  OF  ARC-WELDING  JOBS 


161 


out.     The  filling  in  of  these  holes  and  their  re-drilling  takes 
very  little  time  and  the  cost  is  extremely  low. 

Some  other  welding  operations  which  have  been  carried 
out  with  success  are  these:  side  bearings  which  have  become 


FIG.  144. — Crankshaft  with  Break  Cut  away  for  Welding. 


FIG.  145. — Completed  Weld  Before  Trimming. 

badly  worn  have  been  built  up,  brakeshoe  heads  and  hangers 
have  been  welded  and  truck  side  frames  have  been  repaired 
in  numerous  cases.  A  large  number  of  uses  for  electric  welding 
are  constantly  presenting  themselves  to  all  railways.  Enough 
instances  have  been  cited  to  demonstrate  the  fact  that  the  art 


162  ELECTRIC   WELDING 

of  welding  has  greatly  increased  the  resources  available  for 
lengthening  the  life  of  equipment. 

ELECTRIC    WELDING    A    SIX-TON    CRANKSHAFT 

A.  six-ton  crankshaft  in  the  plant  of  the  Houston  Ice  Co., 
Houston,  Tex.,  broke  through  at  one  of  the  webs.  As  there 
was  no  means  at  hand  to  repair  the  break,  the  crankshaft 
was  shipped  to  the  Vulcan  Iron  Works,  Jersey  City,  N.  J., 
where  it  was  electrically  welded  by  the  Wilson  plastic-arc 
process. 

The  broken  web,  cut  away  preparatory  to  welding,  is  shown 
in  Fig.  144,  and  the  finished  weld  in  Fig.  145.  Owing  to  the 
size  of  the  shaft,  great  care  had  to  be  exercised  in  keeping 
it  in  proper  alignment.  Fig.  146  shows  it  leveled  and  clamped 
to  a  large  surface  plate.  A  straight-edge  is  shown  laid  across 
the  webs  to  assist  the  operator  in  judging  and  keeping  the 
alignment. 

A  big  feature  in  electric  welding  of  this  kind  is 'that  owing 
to  the  intense  heat  of  the  arc,  no  preheating  is  required  as  in 
using  other  methods.  This,  of  course,  greatly  reduces  the  time 
required  to  complete  a  repair  of  this  kind. 

ARC-WELDING    HIGH-SPEED    TOOL    TIPS 

One  large  manufacturer  has  installed  a  Westinghouse  arc- 
welding  equipment  for  the  sole  purpose  of  making  tools  for 
turning  heavy  work.  Ordinarily  these  tools  are  made  from 
high-speed  steel,  and  cost  about  $12  each.  This  manufacturer 
uses  high-speed  steel  for  the  tip  of  the  tool  only,  welding 
it  to  a  shank  of  carbon  or  machine-steel,  as  shown  in  Fig.  147, 
and  in  this  manner  the  tools  are  produced  at  a  cost  of  $2 
to  $4. 

For  several  weeks  this  plant  has  been  turning  out  240 
welded  tools  a  day,  the  men  working  in  shifts  of  four,  which 
is  the  capacity  of  this  outfit. 

The  equipment  consists  of  a  500-amp.  arc-welding  motor 
generator  with  standard  control  panel,  and  three  outlet  panels 
for  metal-electrode  welding,  and  one  special  outlet  panel  for 
the  use  of  either  metal  or  graphite  electrodes.  The  special 
panel  is  intended  to  take  care  of  special  filling  or  cutting 


EXAMPLES  OF  ARC-WELDING  JOBS 


163 


164  ELECTRIC   WELDING 

processes  that  may  be  necessary,  but  ordinarily  it  is  used  in 
the  same  manner  as  other  panels  for  making  tools.  These 
panels  are  distributed  about  the  shops  at  advantageous  points. 
For  toolmaking,  which  involves  the  hardest  grades  of  steel, 
a  preheating  oven  is  used,  not  because  it  is  necessary  for  mak- 
ing a  perfect  weld,  but  because  otherwise  the  hard  steel  is 
likely  to  crack  from  unequal  cooling  and  also  because  pre- 


FIG.  147.— Welding  High-Speed   Tips  Onto  Mild   Steel  Shanks. 

heating  makes  it  easier  to  finish  the  tool  after  the  welding 
process  has  been  completed.  For  ordinary  arc  welding  opera- 
tions the  preheating  oven  is  never  used. 

ELECTRICALLY  WELDED   MILL  BUILDING. 

A  small  all-welded  mill  building  was  erected  in  Brooklyn 
in  1920  for  the  Electric  Welding  Co.,  of  America,  by  T. 
Leonard  MacBean,  engineer  and  contractor.  The  structure  is 
about  60  X  40  ft.,  and  has  four  roof  trusses  of  40-ft.  span 
supported  on  88-in.  H-beam  columns  fitted  with  brackets  for  a 
five-ton  traveling  crane.  In  its  general  arrangement  the  struc- 
ture follows  regular  practice,  but  the  detailing  is  such  as  to 
suit  the  use  of  welding,  and  all  connections  throughout  are 
made  by  this  process.  A  considerable  advantage  in  cost  and 
time  is  claimed  for  the  welded  connections,  but  in  the  present 


EXAMPLES  OF  ARC-WELDING  JOBS  165 

instance  the  determinative  feature  was  not  cost  economy  so 
much  as  the  fact  that  the  fabricated  work  could  be  obtained 
more  quickly  by  buying  the  plain  steel  members  and  cutting 
and  welding  them  at  the  site  instead  of  waiting  for  bridge  shop 
deliveries. 

The  roof  was  designed  for  a  total  load  of  45  Ib.  per  sq.  ft., 
of  which  about  30  Ib.  represents  live  load.    Each  truss  weighs 
1,400  Ib.    The  chords  are  4X5Xf-in.  tees,  while  the  web  mem- 
bers are  single  3X2Xf-in.  angles.     On  the  trusses  rest  10-in. 
15-lb.  channel  purlins  spanning  the  20-ft.  width  of  bay.     The 
columns  are  8x8-in.  H-beams,  19  ft.  high,  and  the  crane  bracket          D 
on  the  inner  face  of  the  column  is  built  up  of  a  pair  of  rear          Q 
connection  angles,  a  pair  of  girder  seat  angles,  and  a  triangular 
web  plate,  as  one  of  the  views  herewith  shows.    Base  and  cap 
of  the  columns  are  made  by  simple  plates. 

All  material  was  received  on  the  job  cut  to  length.  A 
wooden  platform  large  enough  to  take  a  whole  truss  was 
built  as  a  working  floor  and  the  chord  members  were  laid 
down  on  it  in  proper  relative  position  to  form  a -truss  when 
connected.  The  top  chord  was  made  of  a  single  length  of  tee, 
bent  at  the  peak  point  after  a  triangular  piece  was  cut  out 
of  the  stem.  At  the  heel  points  of  the  truss  the  stem  of  the 
top-chord  tee  was  lapped  past  the  stem  of  the  bottom  chord 
tee,  and  when  the  two  members  were  clamped  together  the 
contact  seams  were  welded;  the  seam  of  the  stem  at  the  peak 
was  also  welded  shut.  Then  the  web  members  were  placed 
in  position  and  clamped,  and  their  connections  to  the  chord 
welded.  The  metallic-electrode  arc  process  was  used  and 
various  welded  parts  are  shown  in  Fig.  148. 

Loading  Tests. — When  the  plans  for  the  building  were  sub- 
mitted to  the  Department  of  Buildings,  Borough  of  Brooklyn, 
the  proposal  to  weld  the  connections  was  approved  only  with 
the  stipulation  of  a  successful  load  test  before  erection.  This 
test  was  carried  out  March  20.  Two  trusses  were  set  up  at 
20-ft.  spacing  and  braced  together,  purlins  were  bolted  in 
place,  and  by  means  of  bags  of  gravel  a  load  of  48  tons  was 
applied.  This  was  sufficient  to  load  the  trusses  approximately 
to  their  elastic  limit.  No  straining  or  other  change  was  observ- 
able at  the  joints,  and  the  test  was  considered  in  every  respect 
successful.  The  deflection  of  the  peak,  0.0425  ft.,  did  not 


166 


ELECTRIC  WELDING 


EXAMPLES  OF  ARC-WELDING  JOBS  167 

change  during  48  hours,  and  upon  removal  of  the  load  at  the 
end  of  that  period  a  set  of  less  than  0.01  ft.  was  measured. 

Speed  of  Arc  Welding. — In  a  paper  read  before  the  Ameri- 
can Institute  of  Electrical  Engineers,  New  York,  Feb.  20,  1919, 
H.  M.  Hobart  says: 

All  sorts  of  values  are  given  for  the  speed,  in  feet  per  hour,  with 
which  various  types  of  joints  can  be  welded.  Operators  making  equally 
good  welds  have  widely  varying  degrees  of  proficiency  as  regards  speed. 
Any  quantitative  statement  must  consequently  be  of  so  guarded  a  character 
as  to  be  of  relatively  small  use.  In  general,  and  within  reasonable  limits, 
the  speed  of  welding  will  increase  considerably  when  larger  currents  arc 
employed.  It  appears  reasonable  to  estimate  that  this  increase  in  speed 
will  probably  be  about  25  to  35  per  cent  for  high  values  of  current.  This 
increase  is  not  directly  proportional  to  the  current  employed  because  a 
greater  proportion  of  time  is  taken  to  insert  new  electrodes  and  the  operator 
is  working  under  more  strenuous  conditions.  Incidentally,  the  operator 
who  employs  the  larger  current  .'Will  not  only  weld  quicker  but  the  weld 
will  have  also  better  strength  and  ductility. 

On  this  point  Mr.  Wagner  writes  as  follows: 

I  would  not  say  that  speed  in  arc  welding  was  proportional  to  the 
current  used.  Up  to  a  certain  point  ductility  and  strength  improve  with 
increased  current,  but  when  these  conditions  are  met,  we  do  not  obtain 
the  best  speed  due  to  increased  heating  zone  and  size  of  weld  puddle. 
Speed  may  fall  off  when  current  is  carried  beyond  certain  points. 

In  a  research  made  by  William  Spraragen  for  the  Welding  Research 
Sub-Committee  on  several  tons  of  half-inch-thick  ship  plate,  the  average 
rate  of  welding  was  only  two  feet  per  hour.  Highly  skilled  welders  were 
employed,  but  they  were  required  to  do  the  best  possible  work,  and  the 
kinds  of  joints  and  the  particular  matters  under  comparison  were  very 
varied  and  often  novel. 

However,  in  the  researches  carried  on  by  Mr.  Spraragen  it  was  found 
that  about  1.9  Ib.  of  metal  was  deposited  per  hour  using  a  5/32-in.  bare 
electrode  and  with  the  plates  in  a  flat  position.  The  amount  of  electrodes 
used  up  was  about  2.7  Ib.  per  hour,  of  which  approximately  16.5  per  cent 
was  wasted  as  short  ends  and  13  per  cent  burnt  or  vaporized,  the  remainder 
being  deposited  at  the  speed  of  1.9  Ib.  per  hour  mentioned  above. 

For  a  12-ft.-cube  tank  of  Hn.  thick  steel  welded  at  Pittsfield,  the 
speed  of  welding  was  3  ft.  per  hour.  The  weight  of  the  steel  in  this 
tank  was  16,000  Ib.  and  the  weight  of  electrode  used  up  was  334  Ib.  of 
which  299  Ib.  was  deposited  in  the  welds.  The  total  welding  time  was 
165  hours  corresponding  to  using  up  electrodes  at  the  rate  of  just  2  Ib. 
per  hour.  The  total  length  of  weld  was  501  ft.,  the  weight  of  electrode 
used  up  per  foot  of  weld  thus  being  0.60  Ib.  The  design  of  this  tank 
comprised  eighteen  different  types  of  welded  joint.  Several  different 


168  ELECTRIC  WELDING 

operators  worked  on  this  job  and  the  average  current  per  operator  was 
150  amp. 

For  the  British  125-ft.-long  Cross-Channel  Barge  for  which  the  shell 
plating  was  composed  of  V4-in.  and  5/M-in.  thick  plates,  described  in  H. 
Jasper  Cox's  paper  read  before  the  Society  of  Naval  Architects  on  Nov. 
15,  1918,  and  entitled  '  '  The  Application  of  Electric  Welding  to  Ship  Con- 
struction," it  is  stated  that:  ''After  a  few  initial  difficulties  had  been 
overcome,  an  average  speed  of  welding  of  7  ft.  per  hour  was  maintained 
including  overhead  work  which  averaged  from  3  to  6  ft.  per  hour.  '  ' 

In  a  report  appearing  on  page  67  of  the  minutes  and  records  of  the 
Welding  Kesearch  Sub-Committee  for  June  28,  1918,  O.  A.  Payne,  of  the 
British  Admiralty,  states:  "A  good  welder  could  weld  on  about  one  pound 
of  metal  in  one  hour  with  the  No.  10  Quasi-Arc  electrode,  using  direct 
current  at  100  volts.  An  electrode  containing  about  1£  oz.  of  metal  is 
used  up  in  about  3  minutes,  but  this  rate  cannot  be  kept  up  continously.  " 

The  makers  of  the  Quasi-Arc  electrode  publish  the  following  data  for 
the  speed  of  arc  welding  in  flat  position  with  butt  joints,  a  60-deg.  angle 
and  a  free  distance  of  |-in. 


Thickness 
of  Plates 
I.  in 

Speed  in  Feet 
per  Hour 
30 

4  in                              . 

18 

i  in.                      .  .  .  . 

6 

1  in  

1.3 

I  cannot,  however,  reconcile  the  high  speed  of  welding  £-in.  plate 
published  in  this  report  as  6  ft.  per  hour,  with  the  report  given  above 
by  the  British  Admiralty  that  a  good  welder  deposits  1  Ib.  of  metal  per 
hour  with  the  Quasi-Arc  electrode.  If  the  rate  given  by  the  manufacturer 
is  correct,  it  would  mean  that  about  four  pounds  of  metal  were  deposited 
per  hour.  On  this  basis  the  rate  must  have  been  computed  on  the  time 
taken  to  melt  a  single  electrode  and  not  the  rate  at  which  a  welder  could 
operate  continuously,  allowing  for  his  endurance  and  for  the  time  taken 
to  insert  fresh  electrodes  in  the  electrode  holder  and  the.  time  taken  for 
cleaning  the  surface  of  each  layer  before  commencing  the  next  layer. 
From  his  observations  I  am  of  the  opinion  that  a  representative  rate  for 
a  good  welder  lies  about  midway  between  these  values  given  respectively 
by  Mr.  Payne,  and  by  the  makers  of  the  Quasi-Arc  electrode,  say  for 
£-in.  plates  some  2  Ib.  per  hour.  This,  it  will  be  observed,  agrees  with 
Mr.  Spraragen's  experience  in  welding  up  some  6  tons  of  ^-in.  ship  plate 
with  a  dozen  or  more  varieties  of  butt  joint  and  Mr.  Wagner's  results  with 
an  8-ton  tank.  Even  this  rate  of  2  Ib.  per  hour  is  only  the  actual  time 
of  the  welding  operator  after  his  plates  are  clamped  in  position.  This 
preliminary  work  and  the  preparation  of  the  edges  which  is  quite  an  under- 
taking, and  requires  other  kinds  of  artisans,  accounts  for  a  large  amount 
of  time  and  should  not  be  under-estimated. 

The  practice  heretofore  customary  of  stating  the  speed  of  welding  in 


EXAMPLES  OF  ARC-WELDING  JOBS  169 

feet  per  hour  has  led  to  endless  confusion  as  it  depends  on  type  of  joint, 
height  of  weld  and  various  details.  A  much  better  basis  is  to  express 
the  speed  of  welding  in  pounds  of  metal  deposited  per  hour.  Data  for 
the  pounds  of  metal  deposited  per  hour  are  gradually  becoming  quite  definite. 
The  pounds  of  metal  per  foot  of  weld  required  to  be  deposited  can  be 
readily  calculated  from  the  drawings  or  specifications.  With  the  further 
available  knowledge  of  the  average  waste  in  electrode  ends  and  from  other 
causes,  the  required  amount  of  the  electrode  material  for  a  given  job  can  be 
estimated. 

Suitable  Current  for  Given  Cases. — For  a  given  type  of  weld,  for 
example,  a  double  V-weld  in  a  £-in.  thick  ship  plate,  it  was  found  that 
in  the  summer  of  1918,  while  some  operators  employed  as  low  as  100  amp., 
others  worked  with  over  150  amp.  Some,  in  making  such  a  weld,  employed 
electrodes  of  only  |-in.  diameter  and  others  preferred  electrodes  of  twice 
as  great  cross-section.  For  the  particular  size  and  design  of  weld  above 
mentioned,  the  Welding  Kesearch  Sub-Committee  had  welds  made  with  200 
to  300  amp.  The  conclusion  appears  justified  that  the  preferable  current 
for  such  a  weld  is  at  least  200  amp.  If  the  weld  of  the  £-in.-thick  plate 
is  of  the  double-bevel  type,  some  50  amp.  less  current  should  be  used  for 
the  bottom  layer  than  is  used  for  the  second  layer,  if  two  layers  are 
used.  For  f-in.-thick  plates,  the  most  suitable  welding  current  is  some 
300  amp.  This  is  of  the  order  of  twice  the  current  heretofore  usually 
employed  for  such  a  weld. 

Mr.  Wagner  writes: 

We  have  made  a  number  of  tests  to  determine  the  effect  of  varying 
current  on  the  strength  of  the  weld.  Tests  were  made  on  a  £-in.  plate 
with  current  values  as  follows:  80,  125,  150,  180,  220,  275  and  300  amp. 
These  tests  show  improvement  in  the  tensile  strength  and  bending  qualities 
of  welds  as  the  current  increases.  The  speed  of  welding  increases  up  to  a 
certain  point  and  then  decreases. 

Effect  on  Arc  Welding  of  Voltage  Employed. — We  have  made  a  number 
of  tests  to  determine  the  influence  of  variable  voltages  on  the  strength 
and  character  of  electric  welds.  The  experiments  were  made  welding  £-in. 
plate  with  150  amp.  held  constant  and  voltage  varying  as  follows:  40,  75,  100, 
125,  150,  200  and  225  volts.  This  test  demonstrates  that  there  is  no  material 
difference  in  the  tensile  strength,  bending  qualities  or  the  appearance  of 
the  welded- in  material.  There  is  this  advantage,  however,  in  the  higher 
voltage,  that  variations  in  the  strength  of  the  arc  do  not  materially  affect 
the  value  of  the  current.  A  curve-drawing  ammeter  was  installed  on  the 
welding  circuit  which  showed  variations  in  current  at  75  volts,  but  at  150 
volts  the  current  curve  was  practically  a  straight  line. 

Preferable  Size  of  Electrode. — On  certain  railways,  a  single  diameter 
of  electrode  is  employed  independently  of  the  size  or  shape  of  the  plates 
or  parts  being  welded.  The  experience  of  other  people  leads  them  to  make 
use  of  several  different  sizes  of  electrodes  according  to  the  size  of  the 
job  and  the  type  of  joint.  Present  British  practice  appears  to  be  to  use 


170  ELECTRIC   WELDING 

such  a  size  of  electrode  as  to  have  a  current  density  of  some  4,000  to 
6,000  amp.  per  square  inch.  The  investigations  of  the  Welding  Research 
Sub-Committee  indicate  that  at  least  10,000  to  12,000  amp.  per  square  inch 
is  suitable  for  electrodes  of  y8-in.  and  5/32-in.  diameter  and  well  up  toward 
10,000  amp.  per  square  inch  for  electrodes  of  8/i6-in.  and  3/4-in.  diameter. 


CHAPTER    IX 
PHYSICAL  PROPERTIES  OF   ARC-FUSED   STEEL 

The  work  of  the  Bureau  of  Standards  in  investigating  the 
physical  properties  of  arc-fused  steel,  was  described  in  Chemical 
and  Metallurgical  Engineering,  by  Henry  S.  Rowdon,  Edward 
Groesbeck  and  Louis  Jordan.  This  was  by  special  permission 
of  Director  Stratton.  The  article  was  substantially  as  follows : 

During  the  year  1918  at  the  request  of  and  with  the  co- 
operation of  the  welding  research  sub-committee  of  the 
Emergency  Fleet  Corporation  an  extensive  program  was  outlined 
by  the  Bureau  of  Standards  for  the  study  of  are-welding. 
Due  to  changed  conditions,  however,  at  the  close  of  the  year 
1918,  the  original  program  was  modified  and  shortened  very 
considerably.  In  drawing  up  the  modified  program,  it  was 
decided  to  make  the  study  of  the  characteristic  properties 
of  the  fused-in  metal  the  primary  object  of  the  investigation, 
the  study  of  the  merits  of  the  different  types  of  electrodes 
being  a  secondary  one.  Since  the  metal  of  any  weld  produced 
by  the  electric-arc  fusion  method  is  essentially  a  casting,  as 
there  is  no  refinement  possible  as  in  some  of  the  other  methods, 
it  is  apparent  that  the  efficiency  of  the  weld  is  dependent  upon 
the  properties  of  this  arc-fused  metal.  Hence  a  knowledge  of 
its  properties  is  of  fundamental  importance  in  the  study  of 
electric-arc  welds. 

Preliminary  Examinations  of  Electric- Arc  Welds. — Numer- 
ous articles  have  appeared  in  technical  literature  bearing  on 
the  subject  of  electric-arc  welding.  Most  of  these,  however, 
are  devoted  to  the  technique  and  comparative  merits  of  the 
method,  manipulations,  equipment,  etc.,  rather  than  to  the 
study  of  the  characteristics  of  the  metal  of  the  weld  itself. 
The  information  on  this  phrase  of  the  subject  is  rather  meager. 

A  considerable  number  of  examinations  were  made  of  welds 
'prepared  by  means  of  the  electric-arc  process  and  representa- 
tive of  different  conditions  of  welding. 

171 


172  ELECTRIC  WELDING 

Most  of  these  were  of  a  general  miscellaneous  nature  and 
the  results  do  not  warrant  including  a  description  of  the 
different  specimens  here.  One  series  of  particular  interest, 
however,  may  well  be  referred  to  in  detail.  As  part  of  this 
study  the  welding  research  sub-committee  submitted  to  the 
Bureau  of  Standards  a  number  of  welds  of  ship-plate  repre- 
sentative of  English  practice  for  examination,  some  of  which 
were  considered  as  very  superior  examples  of  welding  as  well 
as  others  of  a  decidedly  inferior  grade.  In  Tables  VII  and 
VIII  are  given  the  results  obtained  by  the  mechanical  tests 
made  upon  these  specimens.  The  welding  was  done  by  skilled 
operators  by  means  of  special  brands  of  electrodes  (welding 
pencils),  the  trade  names  of  which,  however,  have  been  omitted 
from  the  tables.  The  specimens  were  examined  microscopically 
very  carefully,  in  addition  to  the  mechanical  tests  made.  The 
results  are  not  included,  however,  as  the  structural  features 
of  the  material  did  not  differ  from  those  to  be  discussed  in 
another  chapter.  The  results  of  the  mechanical  tests  given 
are  of  value  in  that  they  are  indicative  of  the  average 
mechanical  properties  which  should  be  expected  in  electric-arc 
welds  of  satisfactory  grade  for  the  shape  and  size  of  those 
examined. 

Method  of  Building  Specimens. — The  specimens  required 
for  the  study  of  the  mechanical  properties  of  the  arc-fused 
metal  were  prepared  for  the  most  part  at  the  Bureau  of 
Standards,  direct  current  being  used  in  the  operation.  The 
apparatus  used  is  shown  dia grammatically  in  Fig.  149.  By 
means  of  the  adjustable  water  rheostat  the  current  could  be 
increased  progressively  from  110  to  300  amp.  By  the  use  of 
automatic  recording  instruments  the  voltage  and  current  were 
measured  and  records  were  taken  at  intervals  during  the 
preparation  of  a  specimen.  The  values  of  current  given  in 
the  tables  are  those  which  were  desired  and  were  aimed  at. 
The  average  deviation  from  this  value  as  recorded  by  the 
curves  was  approximately  5  amp.  The  value  of  the  current 
at  the  instant  "the  arc  was  struck'*  was  of  course  many  times 
the  normal  working  value  used  during  the  fusion. 

Since  the  investigation  was  concerned  primarily  with  the 
properties  of  the  arc-fused  metal,  regular  welds  were  not  made. 
Instead  the  metal  was  deposited  in  a  block  large  enough  to 


PHYSICAL   PROPERTIES   OF   ARC-FUSED   STEEL 


173 


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174 


ELECTRIC  WELDING 


permit  a  tension  specimen  (0.505  in.  diameter,  2  in.  gage  length) 
to  be  machined  out  of  it.  Although  the  opinion  is  held  by 
some  welders  that  the  properties  of  the  metal  of  an  arc-weld 
are  affected  materially  by  the  adjacent  metal  by  reason  of 
the  interpenetration  of  the  two,  it  was  decided  that  the  change 
of  properties  of  the  added  metal  induced  by  the  fusion  alone 
was  of  fundamental  importance  and  should  form  the  basis 
of  any  study  of  arc-welding.  The  method  adopted  also  per- 
mitted the  use  of  larger  specimens  with  much  less  machining 


-Weight 


HO  V. 
DC. 


A  tfj  us  to  hie    Wa  ter  ffheos  fat 
?°/o  Sodium  Chloride 
Solution 


feet  Welding 
ToblQ    . 


FIG.  149. — Arrangement  of  Apparatus  for  Welding. 

than  would  have  been  possible  had  the  metal  been  deposited 
in  the  usual  form  of  a  weld. 

In  the  first  few  specimens  prepared  (ten  in  number)  the 
metal  was  deposited  by  a  series  of '"headings"  inside  a  l^-in. 
angle  iron.  The  tension  specimens  cut  from  the  deposited 
metal  were  found  to  be  very  inferior  and  entirely  unsuitable 
for  the  study.  This  was  largely  on  account  of  the  excessive 
overheating  which  occurred  as  well  as  the  fact  that  a  relatively 
"long  arc"  was  necessary  for  the  fusion  in  this  form.  Because 
of  the  very  evident  inferiority  of  these  specimens,  the  results 
of  the  mechanical  tests  made  are  not  given  in  the  tables. 
The  method  of  deposition  of  the  metal  was  then  changed  to 


PHYSICAL  PROPERTIES  OF  ARC-FUSED  STEEL 


175 


that  shown  in  Fig.  150.  This  method  also  had  the  advantage 
in  that  the  amount  of  necessary  machining  for  shaping  the 
specimens  for  test  was  materially  reduced.  The  block  of  arc- 


Side  View 


12"- >, 

End   View 
FIG.  150. — Method  of  Formation  of  the  Blocks  of  Arc-Fused  Metal. 

fused  metal  was  built  up  on  the  end  of  a  section  of  J-in. 
plate  of  mild  steel  (ship  plate)  as  shown.  When  a  block  of 
sufficient  size  had  been  formed,  it,  together  with  the  portion 


FIG.  151. — Block  of  Arc-Fused  Metal  with  Tension  Specimen  Cut  from  It. 
Approximately  Half  Natural  Size. 

of  the  steel  plate  immediately  beneath,  was  sawed  off  from 
the  remainder  of  the  steel  plate.  The  tension  specimen  was 
turned  entirely  out  of  the  arc-fused  metal.  No  difficulty  what- 
ever was  experienced  in  machining  the  specimens.  Fig.  151 


176  ELECTRIC   WELDING 

shows  the  general  appearance  of  the  block  of  fused  metal  as 
well  as  the  tension  specimen  turned  out  of  it. 

In  general  in  forming  the  blocks,  the  fused  metal  was 
deposited  as  a  series  of  " beads"  so  arranged  that  they  were 
parallel  to  the  axis  of  the  tension  specimen  which  was  cut 
later  from  the  block.  In  two  cases,  for  purposes  of  comparison, 
the  metal  was  deposited  in  " beads"  at  right  angles  to  the 
length  of  the  specimen.  In  all  the  specimens,  after  the  deposi- 
tion of  each  layer,  the  surface  was  very  carefully  and  vigor- 
ously brushed  with  a  stiff  wire  brush  to  remove  the  layer  of 
oxide  and  slag  which  formed  during  the  fusion.  There  was 
found  to  be  but  little  need  to  use  the  chisel  for  removing  this 
layer. 

Two  types  of  electrodes  were  used  as  material  to  be  fused. 
These  differed  considerably  in  composition  as  shown  in  Table 
IX,  and  were  chosen  as  representative  of  a  "pure"  iron  and 
a  low-carbon  steel.  The  two  types  will  be  referred  to  as  "A" 
and  "B"  respectively  in  the  tables.  They  were  obtained  in  the 
following  sizes:  Y8,  5/32,  3/16  and  V4  in-  ("A"  electrode  5/ic 
in. ) .  It  was  planned  to  use  the  different  sizes  with  the  follow- 
ing currents:  Y4  in. — 75,  110  and  145  amp.;  5/32  in- — 145,  185 
and  225  amp.;  3/16  in.— 185,  225  and  260  amp.;  y4  in.  (5/ie 
in.) — 300  amp.  The  electrodes  were  used  both  in  the  bare 
condition  and  after  being  slightly  coated  with  an  oxidizing 
and  refractory  mixture.  For  coating,  a  "paste"  of  the  follow- 
ing composition  was  used:  15  g.  graphite,  7.5  g.  magnesium, 
4  g.  aluminium,  65  g.  magnesium  oxide,  60  g.  calcium  oxide. 
To  this  mixture  was  added  120  c.c.  of  sodium  silicate  (40  deg. 
Be.)  and  150  c.c.  of  water.  The  electrodes  were  painted  on 
one  side  only  with  the  paste.  The  quantity  given  above  was 
found  to  be  sufficient  for  coating  500  electrodes.  The  purpose 
of  the  coating  was  to  prevent  excessive  oxidation  of  the  metal 
of  the  electrode  during  fusion  and  to  form  also  a  thin  protective 
coating  of  slag  upon  the  fused  metal. 

Tension  specimens  only  were  prepared  from  the  arc-fused 
metal.  It  is  quite  generally  recognized  that  the  tension  test 
falls  very  short  in  completely  defining  the  mechanical  proper- 
ties of  any  metal;  it  is  believed,  however,  that  the  behavior 
of  this  material  when  stressed  in  tension  is  so  characteristic 
that  its  general  behavior  under  other  conditions  of  stress, 


PHYSICAL  PROPERTIES   OF   ARC-FUSED   STEEL 


177 


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178  ELECTRIC  WELDING 

particularly  when  subjected  to  the  so-called  dynamic  tests — 
i.e.,  vibration  and  shock — can  be  safely  predicted  from  the 
results  obtained.  In  order  to  supplement  the  specimens  made 
at  the  Bureau  a  series  of  six  were  also  prepared  by  one  of 
the  large  manufacturers  of  equipment  for  electric  welding  to 
be  included  in  the  investigation.  These  are  designated  as 
"C"  in  the  tables. 

In  Table  IX  it  will  be  noted  that  the  general  effect  of 
the  fusion  is  to  render  the  two  materials  used  for  welding 
pencils  more  nearly  the  same  in  composition.  The  loss  of 
carbon  and  of  silicon  is  very  marked  in  each  case  where  these 
elements  exist  in  considerable  amounts.  A  similar  tendency 
may  be  noted  for  manganese.  The  coating  with  which  the 
electrodes  were  covered  appears  to  have  but  little  influence, 
if  any,  in  preventing  the  oxidation  of  the  carbon  and  other 
elements. 

TABLE  X — RELATION  BETWEEN  NITROGEN-CONTENT  AND  CURRENT 

DENSITY  * 


Size  of 

Elec.-       Amperes  Cunent 
trode.  In.  (Approx)  Density 

NitrogenContent  (Per  Centt)  
A"  Spec.         "B"  Spec.       "C"  Spec.   Average 

t              110            9,000 

0   156 
0   149§ 

0.152    \            .... 
0.141§  J 

0   138 

J              145          11,800 

0   127 
0   140$ 

0.132    \            
0   I35§  f 

0   126 

A              145            7,600 

0.140 
0   121§ 

0   124    \            
0   122§  1 

0.127 

A              185            9,650 

0   123 
0   I19.J 

0   121    \             
0   1&3II 

0   131 

0   I32j:  1 

A              225          11,700 

0   124 
0   M3§ 

0   117    \             
0   123§  | 

: 

A              175            9.100 

(  0   133 

b 

\  0  098 

A              185            6.700 

0.126 
0   127§ 

0   119    \             
0.  106§  | 

0  120 

A             225           8,150 
A              260            9,400 

0   131 
0   I3I§ 
0   133 
10.134§ 

0.111                  
0   108§  I 
0.112    \            
0.094    / 

0  120 
0.118 

A              300           3,900 

0  117 
10   Ml§ 

0  114 

*  Credit  due  J.  R.  Cain. 

t  Average  of  two  determinatio 

is. 

j  Included  in  average  for  C-D  1  1  ,800. 
§  Coated  electrodes. 

6  Included  in  average  for  C-D  9,000. 
a  Average  of  9  determinations. 

The  most  noticeable  change  in  composition  is  the  increase 
in  the  nitrogen  content  of  the  metal.  In  general  the  increase 
was  rather  uniform  for  all  specimens.  In  Table  X  are  sum- 
marized the  results  of  the  nitrogen  determinations  together 


PHYSICAL   PROPERTIES  OF  ARC-FUSED   STEEL          179 


TABLE  XI — TENSILE  PROPERTIES  OF  ELECTRODES 


»-  Electrode—* 

Ulto. 

-Proper. 

Elong. 

Reduct. 

Size. 
In. 

Strength, 
Lb.  Sq.In. 

Limit, 
Lb.  Sq.In. 

in  2  In. 
Per  Cent 

Area, 
Per  Cent 

A 

A 

65,800 

39,000 

16.5 

69  2 

A 

1 

62,100 

48.000 

9.0 

69.3 

A 

A 

60,100 

34,500 

14  0 

66  4 

A 

A 

57,300 

15  5 

67  6 

B 

& 

88,600 

67,000 

45 

51.  J 

B 

A 

84,700 

58,500 

7.0 

59  8 

R 

i 

66,300 

37,500 

15.0 

61   4 

B 

i 

67,900 

15  5 

62.4 

with  the  corresponding  current  density  used  for  the  fusion 
of  the  metal.  In  Fig.  152  the  average  nitrogen  contents  found 
for  the  different  conditions  of  fusion  are  given  and  plotted 
against  the  corresponding  current  density.  Though  no  definite 
conclusion  seems  to  be  warranted,  it  may  be  said  that,  in 


0.150 


0.130 


0.110 


0.090 


12,000 


?00  6000  8000  10,000 

Current    Density  .Amperes  per  Sq.In. 

FIG.  152. — Relation    of   Current   Density   to    Nitrogen    Content   in 

Arc-Fused  Jron. 
Black  dots   represent  averages. 

general,  the  percentage  of  nitrogen  taken  up  by  the  fused 
iron  increases  somewhat  as  the  current  density  increases.  With 
the  lowest  current  densities  used  the  amount  of  nitrogerTwas' 
Touncf  to  ^ecrease~~KppTGci ably . 

Mechanical  Properties  of  the  Arc-Fused  Metal.— The 
mechanical  properties  of  the  two  types  of  electrodes  used  as 
determined  by  the  tension  test  are  summarized  in  Table  XL 


180 


ELECTRIC   WELDING 


TABLE  XII — TENSILE  PROPERTIES  AND  HARDNESS  OF  FIFTY  SPECIMENS 
OF  WELD-METAL  AT  THE  BUREAU.  (0.505-iN.  DIAM.  STANDARD  TENSION 
BAR  USED) 


Bare  Electrodes 

£             Tensile  Properties 

1 

1 

1 

! 

6               1 

d 

I 

1 

<** 

8 

i 

«               & 

fi 

1               * 

| 

c 

"J 

^ 

•1      i 

i 

2       l 

5          > 

1 

|j 

go 

i 

c 

CO 

A2 

110 

49,850        36,600 

25.000 

60 

65 

108 

A3 

145 

51.950        36,250 

30,000 

80 

13  0 

114 

fl        fc 

145 
185 

47.550         
48.100       ,  

6.0 
8.0 

•74 
87 

108 
104 

A9                A 

225 

45,500       '.:.  . 

80 

96 

io< 

A4                 A 

185 

50,600        33,750 

29,500 

5.5 

13  5 

105 

A5                 A 

225 

49,150        36,250 

22,000 

7.0 

10  0 

102 

A6                A 

260 

50.950        33,750 

28,800 

10.5 

12.0 

107 

AIO              A 

300 

46,670         ..... 

12.0 

119 

104' 

Covered  Electrodes 

AD2               j 

110 

51,250       35,000 

25,600 

9.5 

II.  0 

103 

AD2-D 

no 

43,000 

23.000 

50 

90 

AD3 

MS 

51,100       33,750 

25,000 

8.5 

10*5 

110 

AD3-D 

145 

46,250           .    .. 

24.250 

7.0 

12  0 

AD7              A 

145 

41,750 

60 

66 

99 

AD7-D         A 

145 

46,950 

25.500 

80 

94 

AD8              A 

185 

44,620 

6.5 

58 

103 

AD8-D          A 

185 

43,600 

23,250 

6.5 

9  0 

AD9              A 

225 

46,900 

95 

10   1 

96 

AD9-D         A 

225 

41,550 

25,500 

5.0 

6.5 

AD4              A 

185 

51,200        35,000 

30,000 

10.5 

10.5 

101 

AD4-D         A 

185 

45,700         

25,500 

8.5 

11.5 

AD5              A 

225 

48.600        35,000 

30,000 

7.0 

10  0 

'96 

AD5-D         A 

225 

46.250         

23,750 

11.5 

12  0 

AD6              A 

260 

47,500        34,500 

31,500 

9.0 

9.0 

97 

AD6-D         A 

260 

50,700 

8.0 

28 

105 

ADIO            A 

300 

45,900         

8.5 

11.5 

98 

Bare  Electrodes 

B2                  i 

110 

52,650       37,000 

27,000 

7.5 

7.5 

1  14 

B3                  i 

145 

54,500        36,000 

27,000 

12  5 

12  0 

106 

B4                A 

145 

46,450        33,500 

26,000 

50 

7  0 

102 

185 

49,600        34,250 

27,000 

75 

9  0 

108 

B6                 A 

225 

49,500        30,500 

28,000 

90 

5 

110 

j? 

185 

47,550         

28,500 

75 

11.5 

95 

B8                A 

225 

42,900 

18,750 

75 

16.2 

101 

B9                A 

260 

47,500         

21,500 

12  0 

13  5 

102 

Covered  Electrodes 

BD2               } 

110 

49,050       33,750 

27,500 

9.0 

12.0 

100 

BD2-D 

110 

44,400         

20,000 

6.5 

9.4 

BD3 

145 

52,100        34.300 

30,500 

12  5 

16  0 

116 

BD3-D 

145 

50,850 

23,500 

13  0 

17  5 

BD4              A 

145 

48,130        31,000 

30,500 

8.0 

10  0 

toi 

BD4-D          A 

145 

41,750         

21,000 

6.0 

95 

BD5              A 

185 

49,086        31,730 

29,000 

12  5 

130 

97 

BD5-D          A 

185 

47,100 

22,500 

II   0 

12  5 

BD6              A 

225 

45,500        30,500 

25,000 

8  5 

10  5 

95 

BD7              A 

185 

49,950 

24,500 

II   5 

21   5 

98 

BD7-D         A 

185 

51,150 

23,750 

14  5 

19  5 

BD8              A 

225 

41,500 

17,850 

6.0 

12  7 

99 

BD8-D(?)     A(?) 

225(?) 

48,750 

21,250 

12.5 

16  0 

BD9              A 

260 

46,350 

24,000 

10.0 

15  0 

99 

Bare  Electrodes 

Cl              A 

175 

48,650        32,650 

23,000 

12.0 

19   1 

C2               A 

175 

45,200        32,400 

23,000 

7.5 

16.6 

85        * 

175 
175 

49,720        32,650 
54,500        32,500 

25,000 
25,000 

90 
110 

13.6 
17  5 

118 

C5                A 

175 

50,900        32,500 

24,000 

15  0 

23.0 

109 

C6                A 

175 

50.500        33.500 

23.000 

12  0 

16  0 

PHYSICAL  PROPERTIES  OF  ARC-FUSED  STEEL         181 


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PERTIES  AND  HARDNESS  OF  FlFTY  SPE 

ARRANGED  TN  ORDER  OF  A 

Tensile  Properties  
—  Yield  Point  .  —  Elongat 
Lb.  Sq.ln.  pei 

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Av  35,000  Av.  33.250  Av.  7.9 
lectrodes  used  (Table  III) 
=  110  amps,  and  145(1)  amps.  &  tn.  rft'am.  —  145 
P 

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182  ELECTRIC   WELDING 

In  Table  XII  are  given  the  results  of  the  mechanical  tests 
made  upon  the  tension  specimens  which  were  turned  out  of  the 
blocks  of  metal  resulting  from  the  fusion  of  the  elec- 
trodes. 

The  specimens  listed,  Cx,  C2 . . . .  Cc  are  the  six  which  were 
prepared  outside  the  Bureau  and  submitted  for  purposes  of 
comparison.  It  was  stated  that  they  were  prepared  from  bare 
electrodes  5/32  in.  diameter  of  type  "B,"  containing  0.17  per  cent 
carbon  and  0.5  per  cent  manganese. 

As  an  aid  for  more  readily  comparing  the  mechanical  prop- 
erties of  the  two  types  of  arc-fused  metal  "A"  and  "B,"  the 
results  have  been  grouped  as  given  in  Table  XIII. 

The  characteristic  appearance  of  specimens  after  testing, 
illustrating  their  behavior  when  stressed  in  tension  till  rupture 
occurs  is  shown  in  Fig.  153.  These  represent  two  views  of 
the  face  of  the  fracture,  one  in  which  the  line  of  vision  is 
perpendicular  to  the  face,  the  other  at  an  angle  of  45  deg., 
together  with  a  side  view  of  the  cylindrical  surface  of  the 
specimen.  The  features  shown  are  characteristic  of  all  the 
specimens  tested,  though  in  some  they  were  much  more  pro- 
nounced than  those  shown.  The  fracture  of  the  specimen  in 
all  cases  reveals  interior  flaws.  In  some  of  the  specimens, 
however,  these  are  microscopic  and  of  the  character  to  be 
discussed  in  a  subsequent  chapter  on  Metallography.  Although 
many  of  the  specimens  (from  the  results  of  Table  XII)  appear 
to  have  a  considerable  elongation,  it  is  seen  from  Fig.  153 
that  the  measured  elongation  does  not  truly  represent  a  prop- 
erty of  the  metal  itself.  It  is  due  rather  to  interior  defects 
which  indicate  lack  of  perfect  union  of  succeeding  additions 
of  metal  during  the  process  of  fusion.  The  surface  markings 
of  the  specimen  after  stressing  to  rupture  are  very  similar 
to  those  seen  in  the  familiar  "flaky  steel." 

Resulting  Physical  Properties  Depend  Essentially  on  Sound- 
ness.— It  appears  from  the  results  above  that,  as  far  as  the 
mechanical  properties  are  concerned,  nothing  was  gained  by 
coating  the  electrodes.  The  results  show  no  decided  superiority 
for  either  of  the  two  types  of  electrodes  used.  This  may  be 
expected,  however,  when  one  considers  that  the  two  are  rendered 


PHYSICAL  PROPERTIES  OF  ARC-FUSED  STEEL         183 

practically  the  same  in  composition  during  fusion  by  the  burn- 
ing out  of  the  carbon  and  other  elements. 

The  results  of  the  tension  tests  upon  the  "C"  series  of 


FIG.  153. — Characteristic  Appearance  of  Tension  Specimen  After  Test. 

At  top,  face  of  fracture,  viewed  normally.  Middle,  fractured  end  of  specimen, 
viewed  at  an  angle  of  45  deg.  At  bottom,  cylindrical  surface  of  specimen.  Mag- 
nification, X  2. 

specimens  which  were  made  outside  of  the  Bureau  and  sub- 
mitted to  be  included  in  the  investigation,  show  no  marked 
difference  between  these  samples  and  those  prepared  by  the 
Bureau.  In  all  cases  the  results  obtained  in  the  tension  test 


184  ELECTRIC  WELDING 

are  determined  by  the  soundness  of  the  metal  and  do  not 
necessarily  indicate  the  real  mechanical  properties  of  the 
material. 

The  results  of  the  hardness  determinations  do  not  appear 
to  have  any  particular  or  unusual  significance.  The  variations 
are  of  the  same  general  nature  and  relative  magnitude  as  the 
variations  observed  in  the  results  of  the  tension  test.  In 
general  the  higher  hardness  number  accompanies  the  higher 
tensile  values,  though  this  was  not  invariably  so.  As  previously 
noted,  specimens  were  prepared  for  the  purpose  of  showing 
the  relation  between  the  direction  in  which  the  stress  is  applied 
and  the  manner  of  deposition  of  the  metal.  The  metal  was 
deposited  in  the  form  shown  in  Fig.  151,  except  that  the 
"beads"  extended  across  the  piece  rather  than  lengthwise, 
hence  the  "beads"  of  fused  metal  were  at  right  angles  to  the 
direction  in  which  the  tensional  stress  was  applied.  The  results 
of  the  tension  tests  show  that  these  two  specimens  (AWt  and 
AW2)  were  decidedly  inferior  to  those  prepared  in  the  other 
manner  as  shown  in  Table  XIV. 

TABLE   XIV. — MECHANICAL  PROPERTIES  OF   ARC-FUSED  METAL   DEPOSITED 
AT  EIGHT  ANGLES  TO  LENGTH  OF  SPECIMEN 


Specimen 

Ult. 
Strength, 
Lb.  Sq.  In. 

Proportional 
Limit, 
Lb.  Sq.  In. 

Elongation 
in  2  in.  (per 
Cent) 

Bed.  of  Area, 
per  Cent 

AW1 

40,450 

22,500 

6.5 

8.5 

AW2 

39,500 

22,500 

4.0 

3.0 

Macrostructure. — The  general  condition  of  the  metal  result- 
ing from  the  arc-fusion  is  shown  in  Figs.  154  and  155,  which 
show  longitudinal  median  sections  of  a  series  of  the  tension 
bars  adjacent  to  the  fractured  end.  The  metal  in  all  of  these 
specimens  was  found  to  contain  a  considerable  number  of 
cavities  and  oxide  inclusions,  these  are  best  seen  after  the 
surfaces  are  etched  with  a  10  per  cent  aqueous  solution  of 
copper-ammonium  chloride.  In  many  of  the  specimens  the 
successive  additions  of  metal  are  outlined  by  a  series  of  very 
fine  inclusions  (probably  oxide)  which  are  revealed  by  the 
etching.  There  appears  to  be  no  definite  relation  between  the 
soundness  of  the  metal  and  the  conditions  of  deposition — i.e., 
for  the  range  of  current  density  used — nor  does  either  type 


PHYSICAL  PKOPEKTiES  OF  ARC-FUSED  STEEL         185 


FIG.  154. — Macrostructure  of  Arc-Fused  Metal,  Type  A. 

Medial  Longitudinal  sections  of  the  tension  bars  indicated  were  used 
XII)  ;  etching,  10  per  cent  aqueous  solution  of  copper-ammonium  chloride. 
nification,  X  2.  From  top  to  bottom  in  order: 

Ai)6 — A  electrode;  iMo  in.,  covered,  260  amp. 

A5 — A  electrode;  iMe  in.,  bare,  225  amp. 

A6 — A  electrode;  Me  in.,  bare,   260  amp. 

A3 — A  electrode;  i  in.,  bare,   145  amp. 

A4 — A  electrode;  Me  in.,  bare,   185  amp. 

AD2 — A  electrode;  i  in.,  covered,  110  amp. 


(Table 
Mag- 


186 


ELECTRIC   WELDING 


of  electrode  used  show  any  decided  superiority  over  the  other 
with  respect  to  porosity  of  the  resulting  fusion.     In  Fig.  156 


Fie.  155. — Macrostructure  of  Arc-Fused  Metal,  Type  B. 


Medial  longitudinal  sections  of  the  tension  bars  indicated  were  used  (Table  XII)  ; 
etching,  10  per  cent  aqueous  solution  of  copper-ammonium  chloride.  Magnification, 
X  2.  From  top  to  bottom  in  order: 

B4 — B  electrode;  %2  in.,  bare,   145  amp. 
B5 — B  electrode;  %z  in.,  bare,   185  amp. 
B2 — B  electrode;   J  in.,  bare,  110  amp. 
B3 — B  electrode;    |  in.,  bare,   145  amp. 
BD6 — B  electrode;  5/te  in.,  covered,  225  amp. 
BD4 — B  electrode;    %'i   in.,  covered,   14T>  amp. 

is  shown  the  appearance  of  a  cross-section  of  one  of  the  blocks 
of  arc-fused  metal  prepared  outside  of  the  Bureau  by  skilled 


PHYSICAL  PROPERTIES   OF  ARC-FUSED  STEEL          187 

welding  operators.  The  condition  of  this  material  is  quite 
similar  to  that  prepared  by  the  Bureau. 

The  microscopic  study  of  the  material  to  be  discussed  in 
a  subsequent  chapter  also  revealed  further  evidence  of  unsound- 
ness  in  all  three  types,  "A,"  nB"  and  "C." 

Discussion  of  Results.— In  any  consideration  of  electric-arc 
welding  it  should  constantly  be  borne  in  mind  that  the  weld- 


FIG.  156. — Macrostructure  of  Arc-Fused  Metal,  Type  C. 

Specimen  Cl  (Table  XII),  cross-section  of  the  block  of  arc-fused  metal  from 
which  the  tension  bar  was  turned;  etched  with  5  per  cent  alcoholic  solution  of 
picric  acid.  Magnification,  X  1.7. 

metal  is  simply  metal  which  has  been  melted  and  has  then 
solidified  in  situ.  The  weld  is  essentially  a  casting,  though 
the  conditions  for  its  production  are  very  different  from  those 
ordinarily  employed  in  the  making  of  steel  castings.  The 
metal  loses  many  of  the  properties  it  possesses  when  in  the 
wrought  form  and  hence  it  is  not  to  be  expected  that  a  fusion 
weld  made  by  any  process  whatever,  will  have  all  the  proper- 
ties that  metal  of  the  same  composition  would  have  when  in 
the  forged  or  rolled  condition.  A  knowledge  of  the  char- 


188  ELECTRIC  WELDING 

acteristic  properties  of  the  arc-fused  iron  is  then  of  funda- 
mental importance  in  the  study  of  the  electric-arc  weld. 

The  peculiar  conditions  under  which  the  fusion  takes  place 
also  render  the  metal  of  the  weld  quite  different  from  similar 
metal  melted  and  cast  in  the  usual  manner.  It  is  seemingly 
impossible  to  fuse  the  metal  without  serious  imperfections. 
The  mechanical  properties  of  the  metal  are  dependent  there- 
fore to  an  astonishing  degree  upon  the  skill,  care  and  patience 
of  the  welding  operator.  The  very  low  ductility  shown  by 
specimens  when  stressed  in  tension  is  the  most  striking  feature 
observed  in  the  mechanical  properties  of  the  material  as 
revealed  by  the  tension  test.  As  explained  above,  the  measured 
elongation  of  the  tension  specimen  does  not  truly  indicate  a 
property  of  the  metal.  Due  to  the  unsoundness,  already 
described  in  the  discussion  of  the  structure,  the  true  properties 
of  the  metal  are  not  revealed  by  the  tension  test  to  any 
extent.  The  test  measures,  largely  for  each  particular  speci- 
men, the  adhesion  between  the  successively  added  layers  which 
value  varies  considerably  in  different  specimens  due  to  the 
unsoundness  caused  by  imperfect  fusion,  oxide  and  other  inclu- 
sions, tiny  enclosed  cavities  and  similar  undesirable  features. 
The  elongation  measured  for  any  particular  specimen  is  due 
largely,  if  not  entirely,  to  the  increase  of  length  due  to  the 
combined  effect  of  the  numerous  tiny  imperfections  which  exist 
throughout  the  sample. 

That  the  metal  is  inherently  ductile,  however,  is  shown 
by  the  behavior  upon  bending  (later  to  be  discussed)  in  the 
microstructure  of  bent  specimens.  The  formation  of  slip-bands 
within  the  ferrite  grains  to  the  extent  which  was  observed 
is  evidence  of  a  high  degree  of  ductility.  It  appears,  however, 
that  the  grosser  imperfections  are  sufficient  to  prevent  any 
accurate  measurement  of  the  real  mechanical  properties  of 
the  metal  from  being  made.  The  conclusion  appears  to  be 
warranted  therefore  that  the  changes  of  composition  which  the 
fusion  entails,  together  with  the  unusual  features  of  micro- 
structure  which  accompany  the  composition  change  are  of 
minor  importance  in  determining  the  strength,  durability  and 
other  properties  of  the  arc  weld. 

In  arc-fusion  welds  in  general,  the  mass  of  weld-metal  is  in 
intimate  contact  with  the  parts  which  are  being  welded  so  that 


PHYSICAL  PROPERTIES  OF  ARC-FUSED   STEEL 


189 


it  is  claimed  by  many  that  because  of  the  diffusion  and  inter- 
mingling of  the  metal  under  repair  with  that  of  the  weld, 
properties  of  the  latter  are  considerably  improved.  The  com- 
parison shown  in  Table  XV  somewhat  supports  this  claim.  The 
nearest  comparison  found  available  with  the  Bureau's  specimen 
are  some  of  those  of  the  welds  designated  as  the  "Wirt- 
Jones"  series  reported  by  H.  M.  Hobart.  These  welds  were 
of  the  45  deg.  double-V  type  made  in  ^-in.  ship  plate;  the 
specimens  for  test  were  of  uniform  cross-section  iXi  in.,  the 
projecting  metal  at  the  joint  having  been  planed  off  even  with 
the  surface  of  the  plates  and  the  test  bars  were  so  taken  that 
the  weld  extended  transversely  across  the  specimen  near  the 
center  of  its  length.  The  electrodes  used  were  similar  to  those 
designated  as  type  "B"  in  the  Bureau's  investigation. 

TABLE  XV.— COMPARISON   OF   WELDS  WITH  TESTS  OF  ARC-FUSED  METAL 
PREPARED  UNDER  SIMILAR  CONDITIONS. 


.  Bureau  of  StanrlorHa  — 

TXTtw*     T^^> 

a 

tie 

C  ^ 

1. 

i      '«      4-      1 

J            e 

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Cu.S 

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H 

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o  c 

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5 

6* 

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*                 110 

52.650 

75 

1 

110 

45,800 

8  0 

Jt               110 

49.050 

90 

1 

115 

58,200 

14 

i*          no 

44,400 

6  5 

I 

115 

59,400 

13 

Average 

48,700 

7  7 

1 

120 

53,700 

7 

A               145 

46,450 

5  0 

120 

57,600 

8 

ft11             145 

A'              «45 

48,130 
41,750 

8  0 

Average 

150 

54,940 
60,900 

10 
8 

Average 

45.440 

6  3 

A 

155 

62,600 

11   5 

A           185 

49.600 

7  5 

A  verage 

61.750 

9.8 

A           185 

49.086 

12  5 

H 

175 

59.800 

9  0 

A           185 

47.100 

11   0 

•Average     

48.395 

10  3 

*  Electrodes  were 

used  in  bare  condition. 

t  Electrodes  were  coated  a 
this  column  were  used  bare 

s  previously  described 

,  those 

not  so   designated  in 

Since  the  specimens  used  in  work  described  in  the  fore- 
going sections  were  prepared  in  a  manner  quite  different  from 
the  usual  practice  of  arc-welding,  no  definite  recommendations 
applicable  to  the  latter  can  be  made.  It  appears,  however, 
from  the  results  obtained  that  the  two  types  of  electrodes  used 
— i.e.,  "pure"  iron  and  low-carbon  steel — should  give  very 
similar  results  in  practical  welding.  This  is  due  to  the  changes 
which  occur  during  the  melting  so  that  the  resulting  fusions 
are  essentially  of  the  same  composition.  The  use  of  a  slight 


190  ELECTRIC  WELDING 

coating  on  the  electrodes  does  not  appear  to  be  of  any  material 
advantage  so  far  as  the  properties  of  the  resulting  fused  metal 
are  concerned.  Since  the  program  of  work  as  carried  out  did 
not  include  the  use  of  any  of  the  covered  electrodes  which 
are  highly  recommended  by  many  for  use  in  arc  welding, 
particularly  so,  for  " overhead  work,"  no  data  are  available 
as  to  the  effect  of  such  coatings  upon  the  properties  of  the 
metal  resulting  from  fusion.  Although  all  of  the  specimens 
used  in  the  examinations  were  made  by  the  use  of  direct 
current,  it  appears  from  the  results  obtained  with  a  consider- 
able number  of  welds  representing  the  use  of  both  kinds  of 
current,  submitted  for  the  preliminary  examinations  which 
were  made,  that  the  properties  of  the  fused  metal  are  inde- 
pendent of  the  kind  of  current  and  are  influenced  primarily 
by  the  heat  of  fusion.  Any  difference  in  results  obtained  by 
welding  with  alternating  current  as  compared  with  those 
obtained  with  direct  current  apparently  depends  upon  the  rela- 
tive ease  of  manipulation  during  welding  rather  than  to  any 
intrinsic  effect  of  the  current  upon  properties  of  the  metal. 


CHAPTER   X 
METALLOGRAPHY  OF  ARC-FUSED  STEEL 

The  same  authors  responsible  for  the  description  of  the 
investigations  at  the  Bureau  of  Standards,  given  in  the  previous 
chapter,  also  furnished  the  data  given  in  this  chapter: 

Fusion  welds  evidently  are  fundamentally  different  from 
other  types  of  joints  in  that  the  metal  at  the  weld  is  essentially 
a  casting.  A  preliminary  study  of  a  considerable  number  of 
specimens  welded  under  different  conditions  confirmed  the 
impression  that  the  arc-fusion  weld  has  characteristics  quite 
different  from  other  fusion  welds. 

In  the  present  study,  of  which  both  the  previous  chapter 
and  this  one  form  a  part,  two  types  of  electrodes,  a  "pure" 
iron  called  "A"  and  a  mild  steel  called  "B,"  were  used,  in 
the  bare  condition,  and  also  after  receiving  a  slight  coating. 
With  these  were  included  a  set  of  similar  specimens  prepared 
outside  of  the  Bureau  by  expert  welding  operators.  During 
the  fusion  the  composition  of  the  metal  of  the  two  types  of 
electrodes  is  changed  considerably  by  the  "  burning-out "  of 
the  carbon  and  other  elements,  the  two  becoming  very  much 
alike  in  composition.  A  very  considerable  increase  in  the 
nitrogen  content  occurs  at  the  same  time,  as  shown  by  chemical 
analysis. 

The  mechanical  properties  of  the  arc-fused  metal  as 
measured  by  the  tension  test  are  essentially  those  of  an  inferior 
casting.  The  most  striking  feature  is  the  low  ductility  of  the 
metal.  All  of  the  specimens  showed  evidence  of  unsoundness 
in  their  structure,  tiny  inclosed  cavities,  oxide  inclusions,  lack 
of  intimate  union,  etc.  These  features  of  unsoundness  are, 
seemingly,  a  necessary  consequence  of  the  method  of  fusion 
as  now  practiced.  They  determine  almost  entirely  the  mechanical 
properties  of  the  arc-fused  metal.  The  observed  elongation  of 
the  specimen  under  tension  is  due  to  the  combined  action  of 

191 


192  ELECTRIC   WELDING 

the  numerous  unsound  spots  rather  than  to  the  ductility  of 
the  metal.  That  the  metal  is  inherently  ductile,  however,  will 
be  shown  by  the  changes  in  the  microstructure,  produced  by 
cold-bending.  By  taking  extreme  precautions  during  the 
fusion,  a  great  deal  of  the  unsoundness  may  be  avoided  and 
the  mechanical  properties  of  the  metal  be  considerably  im- 
proved. The  specimens  described,  however,  are  more  repre- 
sentative of  actual  present  practice  in  welding. 

General  Features  of  Microstructure. — For  purposes  of  com- 
parison the  microstructure  of  the  electrodes  before  fusion  is 
shown  in  (1)  and  (2),  Fig.  157.  The  "A"  electrodes  have 
the  appearance  of  steel  of  a  very  low  carbon  content ;  in  some 
cases  they  were  in  the  cold-rolled  state ;  all  showed  a  consider- 
able number  of  inclusions.  The  "B"  electrodes  have  the  struc- 
ture of  a  mild  steel  and  are  much  freer  from  inclusions  than 
are  those  of  the  other  type.  It  is,  undoubtedly  true,  however, 
that  the  condition  of  the  arc-fused  metal  with  respect  to  the 
number  of  inclusions  is  a  result  of  the  fusion  rather  than  of 
the  initial  state  of  the  metal. 

It  is  to  be  expected  that  the  microstructure  of  the  material 
after  fusion  will  be  very  considerably  changed,  since  the  metal 
is  then  essentially  the  same  as  a  casting.  It  has  some  features, 
however,  which  are  not  to  be  found  in  steel  as  ordinarily  cast. 
The  general  type  of  microstructure  was  found  to  vary  in  the 
different  specimens  and  to  range  from  a  condition  which  will 
be  designated  as  "columnar"  to  that  of  a  uniform  fine  equi- 
axed  crystalline  arrangement  as  shown  at  3  and  4,  Fig.  157A. 
This  observation  held  true  for  both  types  of  electrodes,  whether 
bare  or  covered.  In  the  examination  of  cross-sections  of  the 
blocks  of  arc-fused  metal,  it  was  noticed  that  the  equi-axed 
type  of  structure  is  prevalent  throughout  the  interior  of  the 
piece  and  the  columnar  is  to  be  found  generally  nearer  the 
surface — i.e.,  in  the  metal  deposited  last.  It  may  be  inferred 
from  this  that  the  metal  of  the  layers  which  were  deposited 
during  the'  early  part  of  the  preparation  of  the  specimen  is 
refined  considerably  by  the  successive  heatings  to  which  it  is 
subjected  as  additional  layers  of  metal  are  deposited.  The 
general  type  of  structure  of  the  tension  bars  cut  from  the 
blocks  of  arc  fused  metal  will  vary  considerably  according 
to  the  amount  of  refining  which  has  taken  place  as  well  as 


METALLOGRAPHY  OF  ARC-FUSED   STEEL 


193 


the  relative  position  of  the  tension  specimen  within  the  block. 
In  addition  it  was  noticed  that  the  columnar  and  coarse  equi- 
axed  crystalline  condition  appears  to  predominate  with  fusion 
at  high-current  densities. 


FIG.   157. —  (1)   "A"  Electrode,  5/32-in.  Diameter.     Annealed  As  Received. 
(2)     "B"     Electrode,    3/i6-in.    Diameter.       Cold-Drawn. 
Picric  Acid  Etching. 


3 


FIG.  15 7 A. — (3)  Columnar  Structure  of  B2.  X66-  Five  Per  Cent  Picric 
Acid  Etching.  (4)  Equi-axed  Structure  of  AD3.  X200-  Two  Per 
Cent  Alcoholic  HN03  Etching. 

Microscopic  Evidence  of  Unsoundness. — In  all  of  the  speci- 
mens of  arc-fused  metal  examined  microscopically  there  ap- 
pear to  be  numerous  tiny  globules  of  oxide  as  shown  in  Figs. 
158  to  160.  A  magnification  of  500  diameters  is  usually  neces- 
sary to  show  these  inclusions.  In  general  they  appear  to  have 


194 


ELECTRIC   WELDING 


Is 


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METALLOGRAPHY  OF  ARC-FUSED   STEEL  195 

no  definite  arrangement,  but  occur  indiscriminately  through- 
out the  crystals  of  iron. 

A  type  of  unsoundness  frequently  found  is  that  shown  in 
(5),  (6)  and  (7),  Fig.  158;  this  will  be  referred  to  as  "metallic- 
globule  inclusions."  In  general  these  globules  possess  a 
microstructure  similar  to  that  of  the  surrounding  metal,  but 
are  enveloped  by  a  film,  presumably  of  oxide.  It  seems  prob- 
able that  they  are  small  metallic  particles  which  were  formed 
as  a  sort  of  spray  at  the  tip  of  the  electrode  and  which  were 
deposited  on  the  solidified  crust  surrounding  the  pool  of  molten 
metal  directly  under  the  arc.  These  solidified  particles  ap- 
parently are  not  fused  in  with  the  metal  which  is  subsequently 
deposited  over  them — i.e.,  during  the  formation  of  this  same 
layer  and  before  any  brushing  of  the  surface  occurs.  By  taking 
extreme  precautions  during  the  fusion,  a  great  deal  of  this 
unsoundness  may  be  avoided  and  the  mechanical  properties  of 
the  metal  may  be  considerably  improved. 

Characteristic  "Needles"  or  "Plates."— The  most  char- 
acteristic feature  of  the  steel  after  fusion  is  the  presence  of 
numerous  lines  or  needles  within  the  crysals.  The  general 
appearance  of  this  feature  of  the  structure  is  shown  in  (8) 
to  (11),  Fig.  159,  inclusive.  The  number  and  the  distribution 
of  these  needles  were  found  to  vary  greatly  in  the  different 
specimens.  In  general,  they  are  most  abundant  in  the  columnar 
and  in  the  coarse  equi-axed  crystals ;  the  finer  equi-axed  crystals 
in  some  specimens  were  found  to  be  quite  free  from  them, 
although  exceptions  were  found  to  this  rule.  In  general,  a 
needle  lies  entirely  within  the  bounds  of  an  individual  crystal. 
Some  instances  were  found,  however,  where  a  needle  appeared 
to  lie  across  the  boundary  and  so  lie  within  two  adjacent 
crystals.  Several  instances  of  this  tendency  have  been  noted 
in  the  literature  on  this  subject.  The  needles  have  an  ap- 
preciable width,  and  when  the  specimen  is  etched  with  2  per 
cent  alcoholic  nitric  acid  they  appear  much  the  same  as 
cementite — i.e.,  they  remain  uncolored,  although  they  may 
appear  to  widen  and.  darken  if  the  etching  is  prolonged  con- 
siderably. The  apparent  widening  is  evidently  due  to  the 
attack  of  the  adjacent  ferrite  along  the  boundary  line  between 
the  two.  The  tendency  of  the  lines  to  darken  when  etched 
with  a  hot  alkaline  solution  of  sodium  picrate,  as  reported 


196 


ELECTRIC   WELD1NU 


FIG.  159  (8  to  11).— Characteristic  "Needles"  or  "Plates"  X  375. 

(8)  BDg  etched  with  5  per  cent  picric  acid  in  alcohol. 

(9)  Specimen   BD8  after  using  for  thermal  analysis,  re-heated  in  vacuo  to  900 
deg.  C.  four  times.     Picric  acid  etching. 

(10)  Same  as   (9)   except  etched  in  hot  alkaline  sodium  picrate  solution. 

(11)  Specimen  of  welded  joint  between   slip-plate.     Additional  very  small  needles 
are  noted.     Etching:  2  per  cent  HNOs  in  alcohol. 


METALLOGRAPHY  OF  ARC-FUSED  STEEL  197 

by  Comstock,  was  confirmed;  (10)  illustrates  the  appearance 
when  etched  in  this  manner.  The  needles  are  sometimes  found 
in  a  rectangular  grouping — i.e.,  they  form  angles  of  90  deg. 
with  one  another.  In  other  cases  they  appear  to  be  arranged 
along  the  octahedral  planes  of  the  crystal — i.e.,  at  60  deg.  to 
one  another.  This  is  best  seen  in  specimens  which  have  been 
heated,  as  explained  below : 

In  some  of  the  specimens  certain  crystals  showed  groups 
of  very  fine  short  needles  as  in  (11).  The  needles  comprising 
any  one  group  or  family  are  usually  arranged  parallel  to  one 
another,  but  the  various  groups  are  often  arranged  definitely 
with  respect  to  one  another  in  the  same  manner  as  described 
above.  Similar  needles  have  been  reported  in  articles  by 
S.  W.  Miller. 

An  attempt  was  made  by  Dr.  P.  D.  Merica  to  determine 
whether  the  so-called  lines  or  needles  were  really  of  the  shape 
of  needles  or  of  tiny  plates  or  scales.  An  area  was  carefully 
located  on  a  specimen  prepared  for  microscopic  examination, 
which  was  then  ground  down  slightly  and  repolished  several 
times.  It  was  possible  to  measure  the  amount  of  metal  removed 
during  the  slight  grinding  by  observing  the  gradual  disap- 
pearance of  certain  of  the  spherical  oxide  inclusions  the 
diameter  of  which  could  be  accurately  measured.  By  slightly 
etching  the  specimen  after  polishing  anew  it  was  possible  to 
follow  the  gradual  disappearance  of  some  of  the  most  prominent 
needles  and  to  measure  the  maximum  " depth"  of  such  needles. 
It  was  concluded  from  the  series  of  examinations  that  the  term 
"plate"  is  more  correctly  descriptive  of  this  feature  of  the 
structure  than  "line"  or  "needle."  The  thickness  of  the  plate 
—i.e.,  the  width  of  the  needle— varies  from  0.0005  to  0.001 
mm.  and  the  width  of  the  plate  ("depth")  may  be  as  great 
as  0.005  mm.  The  persistence  of  the  plates  after  a  regrinding 
of  the  surface  used  for  microscopical  examination  may  be  noted 
in  some  of  the  micrographs  given  by  Miller.  The  authors  are 
not  aware,  however,  of  any  other  attempt  to  determine  the 
shape  of  these  plates  by  actual  measurements  of  their 
dimensions. 

Plates  Probably  Due  to  Nitrates. — The  usual  explanation 
of  the  nature  of  these  plates  is  that  they  are  due  to  the  nitrogen 
which  is  taken  up  by  the  iron  during  its  fusion.  Other  sug- 


198  ELECTRIC  WELDING 

gestions  which  have  been  offered  previously  attribute  them  to 
oxide  of  iron  and  to  carbide.  The  suggestion  concerning  oxide 
may  be  dismissed  with  a  few  words.  The  plates  are  distinctly 
different  from  oxide  in  their  form  and  their  behavior  upon 
heating.  It  is  shown  later  that  the  tiny  oxide  globules  coalesce 
into  larger  ones  upon  prolonged  heating  in  vacuo;  the  plates 
also  increase  in  size  and  become  much  more  distinct  (see  (32), 
(34)  and  (36),  Fig.  166).  In  no  case,  however,  was  any  inter- 
mediate  stage  between  the  globular  form  and  the  plate  pro- 


FiG.  160. —  (12)  Specimen  AD3,  Etched  with  2  Per  Cent  Alcooholic  Nitric 
Acid.  Shows  Pearlite  Islands,  " Needles"  and  Oxide  Inclusions. 
X750. 

duced  such  as  would  be  expected  if  both  were  of  the  same 
chemical  nature. 

Regarding  the  assumption  that  they  are  cementite  plates, 
it  may  be  said  that  the  tendency  during  fusion  is  for  the  carbon 
to  be  "burned  out,"  thus  leaving  an  iron  of  low  carbon  content. 
In  all  the  specimens,  islands  of  pearlite  (usually  with  cementite 
borders)  are  to  be  found  and  may  easily  be  distinguished  with 
certainty.  The  number  of  such  islands  in  any  specimen  appears 
to  be  sufficient  to  account  for  the  carbon  content  of  the 
material  as  revealed  by  chemical  analysis.  In  some  cases  the 
peariite  islands  are  associated  with  a  certain  type  of  "  lines " 


METALLOGRAPHY  OF  ARC-FUSED  STEEL  199 

or  "needles"  such  as  are  shown  in  (12),  Fig.  160.  These 
needles,  however,  appear  distinctly  different  from  those  of  the 
prevailing  type  and  are  usually  easily  distinguished  from  them. 
The  fact  that  the  plates  found  in  the  arc-fused  metal  are 
identical  in  appearance  and  in  behavior  (e.g.,  etching)  as 
those  found  in  iron  which  has  been  nitrogenized  is  strong 
evidence  that  both  are  of  the  same  nature.  (13)  Fig.  161 
shows  the  appearance  of  the  plates  produced  in  electrolytic 
iron  by  heating  it  for  some  time  in  pure  ammonia  gas.  These 
plates  behave  in  the  same  characteristic  manner  when  etched 
with  hot  sodium  picrate  as  do  those  occurring  in  arc-fused 


13.  mr  14 


FIG.  161. —  (13)  Characteristic    Structure   of   Electrolytic    Iron   Heated   in 

KH3  at  650  Deg.  C.     Two  Types  of  Nitride  Plates.     Etched  with  2 

Per  Cent  Alcoholic  HNO3.     X  375- 
FIG.  161. — (14)  Arc-Fused  Iron  Produced  in  CO2  Atmosphere.    Type  "A," 

Ysa-in.  Electrodes,  150  Amperes.     Etched  with  5  Per  Cent  Picric  Acid 

in  Alcohol.     X  375- 

iron — i.e.,  they  darken  slightly  and  appear  as  finest  rulings 
across  the  bright  ferrite.  The  fact  that  the  nitrogen  content 
of  the  steel  as  shown  by  chemical  analysis  is  increased  by  the 
arc-fusion  also  supports  the  view  that  the  change  which  occurs 
in  the  structure  is  due  to  the  nitrogen.  The  statement  has 
been  made  by  Ruder  that  metal  fused  in  the  absence  of  nitrogen 
— i.e.,  in  an  atmosphere  of  carbon  dioxide  or  of  hydrogen — 
does  not  contain  any  plates  and  hence  the  view  that  the  plates 
are  due  to  the  nitrogen  is  very  much  strengthened.  In  (15), 
Fig.  162,  the  appearance  of  specimens  prepared  at  the  Bureau 
by  arc  fusion  of  electrodes  of  type  "A"  in  an  atmosphere  of 


200 


ELECTRIC  WELDING 


METALLOGRAPHY   OF  ARC-FUSED   STEEL  201 

carbon  dioxide  is  shown.  The  microscopic  examination  of  the 
fused  metal  shows  unmistakable  evidence  of  the  presence  of 
some  plates,  although  they  differ  somewhat  from  those  found 
in  nitrogenized  iron  and  in  metal  fused  in  the  air  by  the 
electric  arc.  Evidently  they  are  due  to  a  different  cause  from 
the  majority  of  those  formed  in  the  iron  fused  in  air.  For 
convenience,  in  the  remainder  of  the  discussion  the  "plates" 
will  be  referred  to  as  "nitride  plates." 

Relation  of  Microstructure  to  the  Path  of  Rupture.— The 
faces  of  the  fracture  of  several  of  the  tension  specimens  after 
testing  were  heavily  plated  electrolytically  with  copper  so  as 
to  preserve  the  edges  of  the  specimens  during  the  polishing 
of  the  section  and  examined  microscopically  to  see  if  the  course 
of  the  path  of  rupture  had  been  influenced  to  an  appreciable 
extent  by  the  microstructural  features.  In  general,  the  frac- 
ture appears  to  be  intcrerystallme  in  type.  Along  the  path 
of  rupture  in  all  of  the  specimens  were  smooth-edged  hollows, 
many  of  which  had  evidently  been  occupied  by  the  "metallic 
globules"  referred  to  above,  while  others  were  gas-holes  or 
pores.  Portions  of  the  fracture  were  intracrystalline  and 
presented  a  jagged  outline,  but  it  cannot  be  stated  with  cer- 
tainty whether  the  needles  have  influenced  the  break  at  such 
points  or  not.  (16)  shows  the  appearance  of  some  of  the 
fractures  and  illustrates  that,  in  general,  the  "nitride  plates" 
do  not  appear  to  determine  to  any  appreciable  extent  the  course 
of  the  path  of  rupture. 

The  behavior  of  the  plates  under  deformation  can  best 
be  seen  in  thin  specimens  of  the  metal  which  were  bent  through 
a  considerable  angle.  Results  of  examination  of  welds  treated 
in  this  manner  have  been  described  by  Miller.  Small  rec- 
tangular plates  of  the  arc-fused  metal,  approximately  3/32  in. 
thick,  were  polished  and  etched  for  microscopic  examination 
and  were  then  bent  in  the  vise  through  an  angle  of  20  deg. 
(approximate). 

In  (18)  to  (21),  Fig.  163,  inclusive  are  given  micrographs 
illustrating  the  characteristic  behavior  of  the  material  when 
subjected  to  bending.  For  moderate  distortion  the  nitride 
plates  influence  the  course  of  the  slip-bands  in  much  the  same 
way  that  grain  boundaries  do — i.e.,  the  slip-bands  terminate 
usually  on  meeting  one  of  the  plates  with  a  change  of  direction 


202 


ELECTRIC  WELDING 


so  that  they  form  a  sharper  angle  with  the  plate  than  does 
the  portion  of  the  slip-band  which  is  at  some  distance  away 
(18).  When  the  deformation  is  greater  the  slip-bands  occur 
on  both  sides  of  the  nitride  plate,  but  usually  show  a  slight 
variation  in  direction  on  the  two  sides  of  the  nitride  plate 
(19)  ;  this  is  often  quite  pronounced  at  the  point  where  the 
plate  is  crossed  by  the  slip-band.  In  a  few  cases  evidence 


a 


19 


2O 


FIG.  163. —  (18  to  21)  Behavior  of  " Nitride  Plates"  During  Plastic  De- 
formation of  the  Iron.  Specimen  RD2,  Etched  with  2  Per  Cent 
Alcoholic,  Nitric  Acid  Before  Bending.  X  500. 

of  the  "faulting"  of  the  plate  as  a  result  of  severe  distortion 
was  noted  (20).  This  was  a  rare  appearance,  however,  because 
of  the  nature  of  the  metal,  and  is  not  shown  in  (21)..  On 
account  of  the  inclusions  and  other  features  of  unsoundness 
of  the  metal,  rupture  occurs  at  such  points  before  the  sound 
crystals  have  been  sufficiently  strained  to  shoAv  the  character- 
istic behavior  of  the  plates.  Other  micrographs  show  the 
beginning  of  a  fracture  around  one  of  the  "metallic  globule" 


METALLOGRAPHY  OF  ARC-FUSED   STEEL  203 

inclusions  before  the  surrounding  metal  lias  been  very  severely 
strained.  For  this  reason  the  influence  of  the  plates  on  the 
mechanical  properties  of  the  crystals  cannot  be  stated  with 
certainty.  It  would  appear,  however,  that  on  account  of  the 
apparently  unavoidable  unsoundness  of  the  metal,  any  possible 
influence  of  the  nitride  plates  upon  the  mechanical  properties 
of  the  material  is  quite  negligible. 

Some  of  the  same  specimens  used  for  cold  bending  were 
torn  partially  in  two  after  localizing  the  tear  by  means  of  a 
saw  cut  in  the  edge  of  the  plate.  The  specimen  was  then 
copper  plated  and  prepared  for  microscopic  examination,  the 
surface  having  been  ground  away  sufficiently  to  reveal  the 
weld-metal  with  the  tear  in  it.  The  nitride  plates  did  not 
appear  to  have  determined  to  any  extent  the  path  taken  in 
the  rupture  produced  in  this  manner. 

Effect  of  Heat  Treatment  Upon  Structure. — With  the  view 
of  possibly  gaming  further  information  as  to  the  nature  of 
the  plates  (assumed  to  be  nitride),  which  constitute  such  a 
characteristic  feature  of  the  microstructure,  a  series  of  heat 
treatments  were  carried  out  upon  several  specimens  of 
arc-fused  electrodes  of  both  types.  Briefly  stated,  the 
treatment  consisted  in  quenching  the  specimens  in  cold 
water  after  heating  them  for  a  period  of  ten  or  fifteen  minutes 
at  a  temperature  considerable  above  that  of  the  Ac3  transforma- 
tion; 925,  950  and  1,000  dcg.  C.  were  the  temperatures  used. 
After  microscopical  examination  of  the  different  quenched 
specimens  they  were  tempered  at  different  temperatures  which 
varied  from  600  to  925  deg.  C.  for  periods  of  ten  and  twenty 
minutes.  The  samples  which  were  used  were  rather  small  in 
size,  being  only  -J  in.  thick,  in  order  that  the  effect  of  the 
treatment  should  be  very  thorough,  were  taken  from  test  bars 
A2,  A3,  AD10,  B2,  B6  and  B9.  These  represented  metal  which 
had  been  deposited  under  different  conditions  of  current  den- 
sity, as  shown  in  Table  X.  No  plates  were  found  to  be  present 
in  any  of  the  specimens  after  quenching.  (22)  Fig.  164  shows 
the  appearance  of  one  of  the  quenched  bars,  a  condition  which 
is  typical  of  all.  The  structure  indicates  that  the  material 
comprising  the  plates  had  dissolved  in  the  matrix  of  iron  and 
had  been  retained  in  this  condition  upon  quenching.  The 
needle-like  striations  within  the  individual  grains  are  char- 


204 


ELECTRIC  WELDING 


METALLOGRAPHY  OF   ARC-FUSED   STEEL  205 

acteristic  of  the  condition  resulting  from  the  severe  quenching 
and  are  to  be  observed  at  times  in  steel  of  a  very  low  carbon 
content.  (23)  shows  the  appearance  of  one  of  the  "A"  elec- 
trodes (V32  in-)  quenched  in  cold  water  from  1,000  deg.  C. 
Some  of  the  crystals  of  the  quenched  iron  also  show  interior 
markings  somewhat  similar  in  appearance  to  the  nitride  plates 
(24).  These  are,  however,  probably  of  the  same  nature  as 
the  interior  tree-like  network  sometimes  seen  in  ferrite  whicli 
has  been  heated  to  a  high  temperature.  The  striations  were 
found  to  be  most  pronounced  in  the  specimens  of  arc-fused 
metal  which  were  quenched  from  the  highest  temperatures, 
as  might  be  expected.  Braune  states  that  nitride  of  iron  in 
quenched  metal  is  retained  in  solution  in  the  martensite.  The 
same  may  be  inferred  from  the  statement  by  Giesen  that  "in 
hardened  steel,  it  (nitrogen)  occurs  in  martensite."  Ruder 
has  also  shown  that  nitrogenized  electrolytic  iron  (3  hr.  at  700 
deg.  C.  in  ammonia)  after  being  quenched  in  water  from  tem- 
peratures 600  to  950  deg.  C.  shows  none  of  the  plates  which 
were  present  before  the  specimen  was  heated. 

The  sets  of  specimens  (A2,  A6,  AD10,  B2,  B6  and  B0) 
quenched  from  above  the  temperature  of  the  Ac3  transforma- 
tion were  heated  to  various  temperatures,  600,  700,  800  and 
925  deg.  C.  In  all  cases  the  specimens  were  maintained  at 
the  maximum  temperature  for  approximately  ten  to  fifteen 
minutes  and  then  cooled  in  the  furnace.  (25)  to  (30),  Fig.  165, 
inclusive  summarize  the  resulting  effects  upon  the  structure. 
Heating  to  650  deg.  C.  is  not  sufficient  to  allow  the  plates 
to  redevelop,  but  in  the  specimens  heated  to  700  deg.  C.  a  few 
small  ones  were  found.  The  effect  is  progressively  more  pro- 
nounced with  the  increased  temperature  of  tempering,  and  in 
the  material  heated  to  925  deg.  C.  they  are  as  large  and  as 
numerous  as  in  any  of  the  arc-fused  specimens.  The  heating 
also  develops  the  islands  of  pearlite  which  are  not  always  to 
be  distinguished  very  clearly  in  the  simple  fused  metal.  The 
work  of  Ruder  shows  that  nitrogenized  iron  which  has  been 
quenched  and  so  rendered  free  from  the  nitride  plates  behaves 
in  a  similar  manner  upon  heating  to  temperatures  varying 
from  700  to  950  deg.  C. ;  the  plates  reappear  after  a  heating 
for  fifteen  minutes  at  700  deg.  C.  (or  above),  followed  by  a 
slow  cooling.  The  similarity  in  behavior  of  the  two  is  a 


206 


ELECTRIC  WELD1JMG 


FlG.  165. —  (25  to  30)   Effect  of  Heat-Treatment  of  Arc-Fused  Iron. 
All  etched  with  2  per  cent  alcoholic  HNOs.      X   450. 

(25)  Specimen  ADio  as  deposited. 

(26)  Same  after  quenching  from  above  HCa   and  reheating  to  650  deg.   C.     No 
"plates"  have  formed. 

(27)  Specimen    ADio    after   quenching   from   above    HCs     and    reheating    to    700 
deg.  C.     "Plates  beginning  to  reform. 

(28)  Specimen  69  after  quenching  from  above  ACs   and  reheating  to  800  dep.  C. 

(29)  Specimen  B2   after  quenching  from  above  ACa   and  reheating  to  925  dep.  C. 

(30)  Specimen  Au  after  quenching  from  above  ACa   and  reheating  to  925  deg.  C. 


METALLOGRAPHY  OF  ARC-FUSED  STEEL  207 


FIG.  1G6.— (31  to  36)  Effect  of  6-hr.  Heating  at  1000  Deg.  C.  in  Vacuo. 

All  etched  with  2  per  cent  alcoholic  HNO3.     X  450. 

(31)  Initial  structure  of  AD2. 

(32)  ADs  after  heating. 

(33)  Initial  structure  of  B*. 

(34)  B4  after  heating. 

(35)  Initial  structure  of  Aio. 

(36)  Aio  after  heating. 


208 


ELECTRIC   WELDING 


further  line  of  evidence  that  the  arc-fused  metal  contains  more 
or  less  nitrogenizcd  iron  throughout  its  mass. 

Plates  Remain  After  Long  Annealing. — The  persistence  of 
the  nitride  plates  was  also  studied  in  specimens  heated  at 
1,000  deg.  C.  in  vacuo  for  a  period  of  6  hr.  A  set  of  specimens 
(one  each  of  test-bars  AD2,  A3,  AD6,  A10,  B2,  B4,  B.,  and  BD5) 
was  packed  in  a  Usalite  crucible,  and  covered  with  alundum 
"sand" ;  this  crucible  was  surrounded  by  a  protecting  alundum 
tube  and  the  whole  heated  in  an  Arsem  furnace.  A  vacuum, 


PIG.  167. — (37)  Effect    of    Pronounced    Heating    Upon    the    Structure    of 

Arc-Fused  Iron. 

Specimen  ADio  was  heated  for  6  hr.  in  vacuo  at  1000  deg.  C.  The  micrograph 
represents  a  section  of  the  specimen  at  one  corner.  The  oxide  and  "nitride  plates" 
have  been  removed  in  the  exposed  tip  of  the  thread.  Etching,  2  per  cent  alcoholic 
solution  of  nitric  acid.  X  150. 

equivalent  to  0.2  mm.  mercury,  was  maintained  for  the  greater 
part  of  the  6-hr,  heating  period;  for  the  remainder  of  the 
time  the  vacuum  was  equivalent  to  0.1  to  0.2  mm.  mercury. 
The  specimens  were  allowed  to  cool  in  the  furnace.  Ruder 
has  stated  that  1  hr.,  heating  in  vacuo  at  1,000  deg.  C.  was 
sufficient  to  cause  a  marked  diminution  in  the  number  of  plates 
in  both  arc-wefd  material  and  nitrogenized  iron  and  that  at 
1,200  deg.  C.  they  disappeared  entirely. 

The  results  obtained  are  shown  in  (31)  to  (36),  Fig.  166, 


METALLOGRAPHY  OF  ARC-FUSED   STEEL  209 

inclusive.  In  contradistinction  to  Ruder 's  work  the  plates  arc 
more  conspicuous  and  larger  than  before,  the  oxide  specks 
are  larger  and  fewer  in  number.  Many  of  the  " plates"  appear 
to  have  been  influenced  in  their  position  by  an  oxide  globule. 
It  would  appear  that  the  conditions  of  the  experiment  are 
favorable  for  a  migration  of  the  oxide  through  an  appreciable 
distance  and  for  a  coalescing  into  larger  masses.  (32),  (34) 
and  (36)  all  show  some  cementite  at  the  grain  boundaries 
which  resulted  from  the  "divorcing"  of  pearlite.  The  oxide 
is  eliminated  entirely  in  a  surface  layer  averaging  approx- 
imately 0.15  mm.  in  depth.  Only  in  projections  (right-angled 
corners,  sections  of  threads  of  the  tension  bar,  etc.),  was  there 
any  removal  of  the  nitride  plates  by  the  action  of  the  continued 
heating  in  vacuo.  This  is  shown  in  (37),  Fig.  167,  which  illus- 
trates the  removal  of  the  oxide  inclusions  also.  No  evidence 
was  found  that  the  small  amount  of  carbon  present  in  the 
arc-fused  metal  is  eliminated,  particularly  beneath  the  surface. 

(6)  Fig.  158  illustrates  an  interesting  exception  to  the  rule 
that  the  nitride  plates  are  flat.  In  the  metallic  and  globular 
inclusion  shown  the  plates  have  a  very  pronounced  curve.  The 
general  appearance  suggests  that  the  " metallic  globules"  solid- 
ified under  a  condition  of  "constraint"  and  that  this  condi- 
tion still  persists  even  after  the  6-hr,  heating  at  1,000  deg.  C. 
which  the  specimen  received. 

Several  of  the  specimens  which  were  heated  in  vacua  (6  hr. 
at  1,000  deg.  C.)  were  analyzed  for  nitrogen.  The  results  are 
given  in  Table  XVI. 

TABLE  XVI. — CHANGE  IN  NITROGEN  CONTENT  UPON  HEATING 


Average 

Nitrogen  Content, 

Wt.  of 

per  Cent 

Sample 

Before 

After  Heating 

Loss 

Specimen 

in  Gr. 

Heating 

in  Vacuo. 

per  Cent 

A3  

1.39 

0.127 

0.062 

51 

B4  

60 

0  124 

0  078 

37 

BD5  

1.62 

0.140 

0059 

57 

B5   . 

1  16 

0  121 

0  054 

55 

The  fact  that  the  specimens  lose  nitrogen  upon  heating 
(although  the  amount  remaining  is  still  many  times  the 
nitrogen-content  of  the  metal  before  fusion),  coupled  with 
the  fact  that  the  " nitride  plates"  are  larger  and  more  con- 


210  ELECTRIC  WELDING 

spicuous  after  heating  than  before,  suggests  very  strongly 
that  these  plates  are  not  simple  nitride  of  iron.  The  method 
used  for  the  determination  of  nitrogen  gives  only  the  "nitride" 
nitrogen,  hence  a  possible  explanation  for  the  change  in 
nitrogen  content  is  that  it  has  been  converted  into  another 
form  than  nitride  and  may  not  have  been  eliminated  from 
the  specimen. 

Thermal  Analysis  of  Arc-Fused  Steel. — In  order  to  throw 
further  light  on  the  nature  of  the  plates  j( nitride)  found  in 
the  metal  after  fusion  in  the  arc,  the  thermal  characteristics 
of  the  electrode  material  before  and  after  fusion  as  revealed 
by  heating  and  cooling  curves  were  determined.  Samples  of 
a  3/16-in.  electrode  of  type  "A"  and  of  the  specimen  A,  which 
resulted  from  the  fusion  were  used  as  material  (composition 
in  Tables  IX  and  XII.) 

TABLE  XVII. — THE  THERMAL  CHARACTERISTICS  OF  ARC-FUSED  IRON 


H 

C 

1 

1 

I 

I 

So 

Ao2,  Maximum 
Deg.  C. 

Beginning 
Maximum,  Deg.  C.  £" 

1 

Maximum  Temp., 
Deg.  C. 

Time  Above  As,- 
Min. 

Beginning 

1 
Maximum.  Deg.  C.  '£ 

Co 

1 

1 

Maximum,  Deg.  C.  ^ 

Unfused  Electrode 

0 

15* 

768 

892   910 

918 

960 

896 

893 

879 

766 

765 

897   911 

916 

960 

895 

891 

879 

766 

Arc-Fused 

Metal  t 

0. 

14 

764 

....   847 

874 

960 

28 

847 

838 

820 

764 

0 

13 

764 

849 

876 

985 

42 

847 

836 

822 

764 

0 

13 

764 

.  .   844 

870 

960 

29 

847 

837 

821 

765 

0 

13 

766 

850 

874 

1.035 

256 

848 

835 

816 

764 

*  Heated  at  rate  of  0   16  dcg.  C.  per  sec.,  cooled  0.15  deg.  C.  per  sec.  for  other 
specimens,  the  rate  of  cooling  equaled  the  rate  of  heating. 

t  The  same  specimen  was  heated  four  times  in  succession,  as  shown.     (Fig  38) 


In  Fig.  168  are  given  the  curves  obtained  which  show  the 
characteristic  behavior  of  the  arc-fused  metal  upon  heating. 
The  commonly  used  inverse-rate  method  was  employed  in  plot- 
ting the  data ;  the  details  of  manipulation  and  the  precautions 
necessary  for  the  thermal  analysis  have  already  been  described. 
In  Table  XVII  are  summarized  the  data  shown  graphically  in 
the  last  cut. 

The  principal  change  to  be  noted  which  has  resulted  from 


METALLOGRAPHY  OF  ARC-FUSED   STEEL 


211 


O 


J  I 

tS      « 


M/ 


•I - 


s- 


EH     * 

o    J> 


?l 


^    E 

m    S 


? 


212  ELECTRIC  WELDING 

the  arc-fusion  of  the  iron  is  in  the  A3  transformation.  This 
is  now  very  similar  to  the  corresponding  change  observed  in 
a  very  mild  steel  (e.g.,  approximately  0.15  per  cent  carbon). 
That  the  difference  in  the  A3  transformation  of  the  arc-fused 
metal  as  compared  with  that  of  the  original  electrode  is  not 
due  to  an  increase  in  the  carbon  content  is  evident  from  the 
lack  of  the  sharp  inflection  of  the  Aa  transformation  ("pear lite 
point ")  which  would,  of  necessity,  be  found  in  a  low  carbon 
steel.  No  evidence  of  the  Ax  change  was  observed  for  the 
arc-fused  iron  within  the  range  of  temperature,  150  to  950 
deg  C.  The  change  in  the  character  of  the  A3  transformation 
is  without  doubt  to  be  attributed  to  the  influence  of  the 
increased  nitrogen-content  of  the  iron. 

The  specimen  was  maintained  above  the  temperature  of 
the  A3  transformation  for  a  total  period  (four  heatings)  of 
6  hr.,  the  maximum  temperature  being  1,035  deg.  C.  The 
transformation  apparently  is  unaffected  by  the  long-continued 
heating,  thus  confirming  the  results  described  in  the  preceding 
section. 

In  discussing  the  properties  of  steel  nitrogenized  by  melting 
it  in  nitrogen  under  pressure,  Andrews  states  that  it  was 
found  possible  to  extract  almost  entirely  the  small  quantities 
of  nitrogen  by  heating  a  specimen  at  1,000  deg.  C.  in  vacuo 
for  periods  of  1  to  6  hr.  The  metal  used  contained  0.16  per 
cent  carbon  and  0.3  per  cent  nitrogen.  Thermal  curves  are 
given  to  show  that  there  are  no  critical  transformations  in 
the  material;  the  nitrogen  suppresses  them.  They  gradually 
reappear,  however,  as  the  nitrogen  is  removed  by  heating  the 
material  in  vacuo  at  1,000  deg.  C.  Several  days'  heating  was 
required,  however,  to  obtain  an  entirely  degasified  product, 
the  carbon  being  removed  also.  A  further  statement  is  made 
that  a  steel  of  0.6  per  cent  carbon  content  containing  0.25  per 
cent  nitrogen  can  be  brought  back  to  the  normal  state  of  a 
pure  steel  only  by  several  weeks'  heating  in  vacuo. 

The  results  of  the  thermal  analysis  add  considerable  con- 
firmatory evidence  to  support  the  view  that  the  plates  existing 
in  the  arc-fused  metal  are  due  to  the  nitrogen  rather  than 
to  carbon. 

Summary. — Microscopic  examination  of  bent  pieces  of  arc- 
fused  metal  show  that  the  metallic  grains  are  inherently  ductile, 


METALLOGRAPHY  OF  ARC-FUSED  STEEL  213 

even  to  a  high  degree.  Grosser  imperfections,  however,  are 
entirely  sufficient  to  mask  this  excellence. 

The  view  that  the  characteristic  features  observed  in  the 
structure  of  the  arc-fused  iron  are  due  to  the  increased  nitrogen 
content  is  supported  by  several  different  lines  of  evidence. 
These  include  the  likeness  of  the  structure  of  the  material 
to  that  of  pure  iron  which  has  been  "nitrogenized,"  the 
similarity  in  the  behavior  of  both  arc-fused  and  nitrogenized 
iron  upon  heating,  the  evidence  shown  by  thermal  analysis 
of  the  arc-fused  metal,  together  with  the  fact  that,  as  shown 
by  chemical  analysis,  the  nitrogen  content ,  increases  during 
fusion,  while  the  other  elements,  aside  from  oxygen,  decrease 
in  amount.  The  characteristic  form  in  which  oxide  occurs  in 
iron,  together  with  its  behavior  upon  heating,  renders  the 
assumption  that  the  oxide  is  responsible  for  the  plates  observed 
in  the  material  a  very  improbable  one. 

Judged  from  the  results  obtained,  neither  type  of  electrode 
appears  to  have  a  marked  advantage  over  the  other.  The  use 
of  a  slight  protective  coating  on  the  electrodes  does  not  appear 
to  affect  the  mechanical  properties  of  the  arc-fused  metal 
materially  in  any  way.  The  specimens  were  prepared  in  a 
manner  quite  different  from  that  used  ordinarily  in  electric-arc 
welding  and  the  results  do  not  justify  any  specific  recom- 
mendations concerning  methods  of  practice  in  welding. 


CHAPTER   XI 
AUTOMATIC    ARC    WELDING 

The  automatic  arc  welding  machine,  made  by  the  General 
Electric  Co.,  Schenectady,  N.  Y.,  is  a  device  for  automatically 
feeding  metallic  electrode  wire  into  the  welding  arc  at  the 
rate  required  to  hold  a  constant  arc  length,  says  H.  L.  Unland 
in  a  paper  read  before  the  American  Welding  Society.  Under 
these  circumstances  the  electrical  conditions  are  kept  constant 
and  the  resulting  weld  is  uniform  and  its  quality  is  thereby 
improved.  It  is  possible  with  this  device  to  weld  at  a  speed 
of  from  two  to  six  times  the  rate  attained  by  skilled  operators 
welding  by  hand.  This  is  partly  due  to  the  stability  of  the 
welding  conditions  and  partly  due  to  the  fact  that  the  elec- 
trode is  fed  from  a  continuous  reel,  thus  eliminating  the  chang- 
ing of  electrodes.  The  automatic  welding  machine  is  adaptable 
to  practically  any  form  of  weld  from  butt  welding  of  plates 
to  the  depositing  of  metal  on  worn  surfaces  such  as  shafts, 
wheels,  etc. 

Everyone  who  has  made  any  investigation  of  electric  arc 
welding  has  noted  the  wide  variation  in  results  obtained  by 
different  welders  operating,  as  nearly  as  can  be  determined, 
under  identical  conditions.  This  also  applies  to  the  operations 
of  a  single  welder  at  different  times  under  identical  conditions. 
These  variations  affect  practically  all  factors  of  welding  such 
as  speed  of  welding,  amount  of  electrode  consumed,  etc.  When 
indicating  instruments  are  connected  to  an  electric  welding 
circuit,  continual  variations  of  considerable  magnitude  in  the 
current  and  voltage  of  the  arc  are  at  once  noticed.  Consider- 
able variation  was  found  some  years  ago  in  the  cutting  of 
steel  plates  by  the  gas  process  and  when  an  equipment  was 
devised  to  mechanically  travel  the  cutting  torch  over  the  plate 
a  series  of  tests  to  determine  the  maximum  economical  speed, 
gas  pressure,  etc.,  for  the  various  thickness  of  plate  were  made. 

214 


AUTOMATIC  ARC  WELDING  215 

The  result  was  that  the  speed  of  cutting  was  increased  to  as 
much  as  four  or  five  times  the  rate  possible  when  operating 
under  the  unsteady  conditions  incident  to  hand  manipulation 
of  the  torch.  Further,  the  gas  consumption  for  a  given  cut 
was  found  to  be  decreased  very  greatly. 

As  a  result  of  many  experiences  an  investigation  was  started 
to  determine  what  could  be  done  in  controlling  the  feed  of 
the  electrode  to  the  electric  arc  in  a  metallic  electrode  welding 
circuit.  An  electric  arc  is  inherently  unstable,  the  fluctuations 
taking  place  with  extreme  rapidity.  In  any  regulating  device 
the  sensitiveness  depends  on  the  percentage  of  variation  from 
normal  rather  than  on  the  actual  magnitude  of  the  values,  since 
these  are  always  reduced  to  approximately  a  common  factor 
by  the  use  of  shunts,  current  transformers,  or  series  resist- 
ances. The  characteristics  of  practically  all  electric  welding 
circuits  are  such  that  the  current  and  voltage  are  inter-related, 
an  increase  in  one  causing  a  corresponding  decrease  in  the 
other.  Where  this  is  the  case  it  will  generally  be  found  that 
the  percentage  variation  of  the  voltage  from  normal  when 
taken  at  the  customary  arc  voltage  of  20,  will  be  approximately 
twice  the  percentage  variation  in  current.  Further,  an  increase 
in  arc  voltage,  other  conditions  remaining  the  same,  indicates 
that  the  arc  has  been  lengthened,  thus  giving  the  metal  a 
greater  opportunity  to  oxidize  in  the  arc  with  a  probability 
of  reduction  in  quality  of  the  weld.  The  automatic  arc  weld- 
ing machine  utilizes  the  arc  voltage  as  the  basis  for  regulating 
the  equipment.  The  rate  of  feeding  the  wire  varies  over  a  wide 
range,  due  to  the  use  of  electrodes  of  different  diameters, 
the  use  of  different  current  values,  etc.,  caused  by  details  of  the 
particular  weld  to  be  made.  The  simplest  and  most  reliable 
method  of  electrically  obtaining  variations  in  speed  is  by 
means  of  a  separately  excited  direct  current  motor.  Thus  the 
operation  of  this  equipment  is  limited  to  direct  current  arc 
welding  circuits,  but  these  may  be  of  any  established  type, 
the  variations  in  characteristics  of  the  welding  circuits  being 
taken  care  of  by  proper  selection  of  resistors,  coils,  etc.,  in 
the  control. 

The  Welding  Head. — The  welding  head  consists  essentially 
of  a  set  of  rollers  for  gripping  the  wire  and  feeding  it  to 
the  arc.  These  rollers  are  suitably  connected  through  gearing 


216  ELECTRIC  WELDING 

to  a  small  direct-current  motor,  the  armature  of  which  is  con- 
nected across  the  terminals  of  the  welding  arc.  This  connec- 
tion causes  the  motor  to  increase  in  speed  as  the  voltage  across 
the  arc  increases  due  to  an  increase  in  the  length  of  the  arc 
and  to  decrease  in  speed  as  the  voltage  decreases,  due  to  a 
shortened  arc.  A  small  relay  operating  on  the  principle  of 
a  generator  voltage  regulator  is  connected  in  the  field  circuit 
of  the  motor  which  assists  in  the  speed  control  of  the  motor 
as  the  arc  voltage  varies.  Rheostats,  for  regulating  and  adjust- 
ing the  are  voltage,  are  provided  by  means  of  which  the 
equipment  can  be  made  to  maintain  steadily  an  arc  of  the 
desired  length  and  this  value  may  be  varied  from  over  twenty 
to  as  low  as  nine  volts.  No  provision  is  made  in  the  machine 
for  adjustment  of  the  welding  current  since  the  automatic 
operation  is  in  no  way  dependent  on  it.  The  welding  current 
adjustment  is  taken  care  of  by  the  control  panel  of  the  welding 
set.  This  may  be  either  of  the  variable  voltage  or  constant 
potential  type  but  it  is  necessary  to  have  a  source  of  constant 
potential  to  excite  the  fields  of  feed  motor.  It  may  be  possible 
to  obtain  this  excitation  from  the  welding  circuit,  but  this 
is  not  essential.  The  voltage  of  both  the  welding  and  constant 
potential  circuits  is  immaterial,  provided  it  is  not  too  high, 
but  these  voltages  must  be  known  before  the  proper  rheostats 
can  be  supplied. 

On  account  of  the  great  variation  in  conditions  under  which 
this  welding  equipment  may  be  used  it  is  provided  with  a 
base  which  may  be  bolted  to  any  form  of  support.  It  may  be 
held  stationary  and  the  work  traveled  past  the  arc  or  welding 
head  may  be  movable  and  the  work  held  stationary.  These 
points  will  be  dictated  by  the  relative  size  of  the  work  and 
the  head  and  the  equipment  which  may  be  available.  Provision 
must  be  made  for  traveling  one  or  the  other  at  a  uniform 
speed  in  order  to  carry  the  arc  along  the  weld.  In  the  case 
of  straight  seams  a  lathe  or  planer  bed  may  be  utilized  for 
this  purpose  and  for  circular  seams  a  lathe  or  boring  mill 
may  be  used.  In  many  cases  it  will  be  found  desirable  to 
use  clamping  jigs  for  securely  holding  the  work  in  shape  and 
also  to  facilitate  placing  in  position  and  removing  from  the 
feeding  mechanism. 

In  Fig.  169,  the  welding  head  is  shown  mounted  on  a  special 


AUTOMATIC  ARC  WELDING 


217 


device  for  making  circular  welds.     The  work  table  is  driven 
through  a  worm  and  worm  gear  by  means  of  a  separate  motor. 


FIG.  169. — Special  Set-Up  of  Machine  for  Circular  Welding. 

The  welding  head  may  be  led  along  the  arm  by  means  of 
the  handwheel,  and  it  may  be  tilted  at  an  angle  of  45  deg. 


218 


ELECTRIC  WELDING 


both  at  right  angles  to  the  line  of  weld  and  also  parallel 
to  the  line  of  weld.  Fig.  170  shows  the  building  up  of  a  shaft, 
the  work  being  mounted  on  lathe  centers  and  the  welding 
head  placed  on  a  bracket  clamped  to  saddle. 

Fig.  171  shows  a  simplified  diagram  of  the  control  of  the 
feed  motor.  In  this  cut  A  is  the  regulating  rheostat  in  the 
motor  field  circuit  controlled  by  the  arc  voltage  regulator  G; 
B  is  the  adjusting  rheostat  in  the  motor  field  circuit  j  F 


FIG.  170. — Set-Up  for  Building  up  a  Shaft. 

indicates  the  feed  motor  field  winding;  M  the  feed  motor  wind- 
ing; D  is  the  resistance  in  the  motor  armature  circuit  to  adjust 
the  speed  when  starting  the  feed  motor  before  the  arc  is  struck. 
The  open-circuit  voltage  of  the  welding  circuit  is  ordinarily 
considerably  higher  than  the  arc  voltage.  This  resistance  D 
is  short  circuited  by  contactor  X  when  the  arc  is  struck.  The 
arc  voltage  regulator  G  maintains  constant  arc  voltage  by 
varying  the  motor  field  strength  through  resistor  A.  The 
regulator  is  adjusted  to  hold  the  desired  voltage  by  the  rheostat 


AUTOMATIC  ARC  WELDING 


219 


C.  Permanent  resistance  E  is  in  series  with  the  over-voltage 
relay  H,  to  compensate  for  the  voltage  of  the  welding  circuit. 
Over  voltage  relay  H  holds  open  the  coil  circuit  of  the  regulator 
G  until  the  electrode  makes  contact  in  order  to  protect  the 
coil  from  burning  out. 

Observation  of  indicating  meters  on  the  control  panel  show 
that  the  current  and  voltage  are  practically  constant,  but  it 
should  be  remembered  that  all  indicating  meters  have  a  certain 
amount  of  damping  which  prevents  observation  of  the  varia- 
tions which  are  extremely  rapid  or  of  small  magnitude.  The 
resultant  value  as  read  on  the  instrument  is  the  average  value. 
Oscillographs  taken  with  short  arcs  show  that  notwithstanding 
the  fact  that  the  indicating  meters  show  a  constant  value,  a 


Ammeter 


FIG.  171. — Simplified  Diagram  of  Control  of  Feed  Motor. 

succession  of  rapid  short  circuits  is  continually  taking  place, 
apparently  due  to  particles  of  the  molten  wire  practically  short- 
circuiting  the  arc  in  passing  from  the  electrode  to  the  work. 
This  is  indicated  by  the  fact  that  the  voltage  curve  fell  to 
zero  each  time,  and  accompanying  each  such  fluctuation  there 
was  an  increase  in  the  current.  It  was  found  that  with  the 
shorter  arc  the  frequency  of  occurrence  of  these  short-circuits 
was  considerably  higher  than  was  the  case  when  the  arc  was 
increased  in  length.  To  all  appearances  the  arc  was  absolutely 
steady  and  continuous  and  there  was  no  indication  either  by 
observation  of  the  arc  itself  or  of  the  instruments  that  these 
phenomena  were  occurring. 

Some  Work  Performed  By  the  Machine, — The  principal 
field  for  an  automatic  arc  welding  machine  is  where  a  consider- 


220  ELECTRIC  WELDING 

able  amount  of  welding  is  required,  the  operations  being  a 
continuous  repetition  of  duplicate  welds.  Under  these  condi- 
tions one  can  economically  provide  jigs  and  fixtures  for 
facilitating  the  handling  of  the  work  and  the  clamping.  Thus 
can  be  reaped  the  benefit  of  the  increased  speed  in  the  actual 
welding  which  would  be  lost  if  each  individual  piece  had  to 
be  clamped  and  handled  separately. 

Examples  of  different  jobs  done  with  this  machine,  using 
various  feeding  and  holding  methods,  are  shown  in  the  accom- 
panying cuts.  Fig.  172  is  a  worn  pulley  seat  on  an  electric 
motor  shaft  built  up  and  ready  to  be  re-turned  to  size. 

It  is  possible  to  build  up  pulley  and  pinion  seats,  also  worn 
bearings,  without  removing  the  armature  or  rotor  from  the 


m 


Fie.  172. — Worn  Motor  Shaft  Built  Up. 

shaft  and  in  practically  all  cases  without  removing  the  wind- 
ings due  to  the  concentration  of  the  heat  at  the  point  of  the 
weld.  On  shafts  of  this  kind,  3  to  4  in.  in  diameter,  the  figures 
are:  current  115  amp.;  arc  voltage  14;  electrode  3/32  in.  in 
diameter;  travel,  6  in.  per  min. ;  rate  of  deposit  about  2.1  Ib. 
per  hour. 

Similar  work  on  a  14-in.  shaft  where  the  flywheel  seat 
21  in.  long  was  turned  undersize,  was  as  follows:  metal  about 
Vie  in-  deep  was  deposited  over  the  undersize  surface,  using 
current,  190  amp.;  arc  voltage  18;  electrode  -J  in.  diameter; 
travel  4  in.  per  min.;  rate  of  deposit,  about  2  Ib.  per  hour; 
welding  time,  16  hr. ;  machining  time,  4  hr. 

Fig.  173  shows  worn  and  repaired  crane  wheel  flanges. 
These  are  easily  handled  by  mounting  on  a  mandrel  in  a  lathe, 


AUTOMATIC   ARC  WELDING 


221 


and  placing  the  welding  machine  on  a  bracket  bolted  to  the 
cross-slide  or  the  saddle.  On  wheels  of  this  type  22  in.  in 
diameter,  the  time  taken  to  weld  by  hand  would  be  about 
12  hr.  and  by  machine  2  hr. ;  machining  time  4  hr. ;  approximate 
cost  by  hand  welding  $9;  by  machine  $4. 


i 


FlG.  173. — Worn  and  Repaired  Crane  Wheels. 


FIG.  174.— Welded  Automobile  Hub  Stampings. 

Fig.  174  is  an  automobile  wire  wheel  hub  stamping,  to 
which  a  dust  cover  was  welded  as  shown.  Joint  was  between 
metal  1/16  and  Vie  in.  thick.  Current  100  amp.;  arc  voltage, 
14 ;  travel  10  in.  per  min. ;  electrode  3/32  in.  diameter. 


222 


ELECTRIC   WELDING 


Fig.  175,  welded  automobile  rear-axle  housing,  3/16  in-  thick ; 
current  120  amp.;  arc  voltage  14;  travel  6  in.  per  min. ;  elec- 
trode diameter  3/82  in. 

Fig.  176,  welded  tank  seam;  metal  -J  in.  thick;  current  140 
arnp. ;  arc  voltage  14 ;  travel,  6  in.  per  min. ;  time  for  welding 
ten  tanks  by  hand,  4  hrs.  40  min. ;  by  machine,  2  hrs. 


FIG.  175. — Welded  Bear- Axle  Housing. 

Tables  XVIII  and  XIX  give  an  idea  of  the  speed  of  welding 
which  may  be  expected,  but  it  should  be  borne  in  mind  that 
these  figures  are  actual  welding  speeds.  It  is  necessary  to 
have  the  material  properly  clamped  and  supported  and  to  have 
it  travel  past  the  arc  at  a  uniform  speed.  In  some  cases  the 


FiG.  176 — Welded  Straight  Tank  Seam. 

figures  given  have  been  exceeded  and  under  certain  special 
conditions  it  may  be  desirable  to  use  lower  values  than  those 
given. 

TABLE  XVIII. — SEAM  WELDING 


Thickness  in  Inches 
0.040 
1/16 
1/8 
3/16 


Amperes  Speed,  Inches  Per  Minute 
45  to     50  20  to  30 

50  to     80  15  to  25 

80  to  120  6  to  12 

100  to  150  4  to     6 


AUTOMATIC  ARC   WELDING  223 

TABLE  XIX — BUILDING  UP    (WHEELS   OR  SHAFTS) 


Diameter  or 

Electrodes, 

Speed,  In.  per 

Lb.  Deposit 

Thick.,  In. 

Dia.,  In. 

Amperes 

Min. 

Per  Hour 

Up  to  1" 

V- 

60  to     90 

11  to  13 

1.04-1.56 

Up  to  3" 

% 

90  to  120 

6  to     8 

1.59-2.1 

Over  3" 

V- 

120  to  200 

4  to     6 

2.5  -4.5 

A  SEMI-AUTOMATIC  ARC-WELDING  MACHINE 

A  paper  on  " Welding  Mild  Steel,"  by  H.  W.  Hobart,  was 
read  at  the  New  York  meeting  of  the  American  Institute  of 
Mining  and  Metallurgical  Engineers  in  1919.  In  discussing 
this  paper  Harry  D.  Morton,  of  the  Automatic  Arc  Welding 
Co.,  Detroit,  brought  out  some  interesting  things  relating  to 
Automatic  Arc  Welding: 

"The  generally  accepted  theory  of  the  electric  arc  is  that  part  of  the 
electrode  material  is  vaporized,  and  that  this  vaporous  tube  or  column 
forms  a  path  for  the  electric  current.  As  a  result  of  the  vaporous 
character  of  the  current  path,  all  arcs  are  inherently  unstable;  and  the 
maximum  of  instability  is  no  doubt  found  in  that  form  of  arc  employed 
for  metallic-electrode  welding  purposes.  We  here  have,  in  conjunction  with 
the  natural  instability  characteristic  of  all  arcs  rapidly  fusing  electrode 
materials  and  the  disturbing  effect  of  the  constant  passage  through  the 
arc  of  a  large  quantity  of  molten  metal  to  form  the  weld.  This  molten 
metal  must  pass  through  the  arc  so  rapidly  that  it  will  not  be  injured 
or  materially  contaminated;  otherwise  the  weld  will  be  useless.  Prima 
facie,  the  combination  of  these  unfavorable  conditions  would  seem  to 
justify  fully  the  skepticism  of  most  electrical  engineers  as  to  the  possibility 
of  affecting  such  control  of  the  metallic  arc  as  to  permit  of  uniformity 
and  continuity  in  welding  results.  In  addition,  there  is  another  and  more 
important  factor,  and  one  that  seriously  mitigates  against  this  desired 
uniformity  and  continuity;  namely,  the  personal  equation  of  the  operator. 
The  consensus  of  opinion,  so  far  as  is  known  to  the  writer,  seems  to  be 
that  about  95  per  cent,  of  the  welding  result  is  dependent  on  the  skill 
of  the  operator  and  that  at  least  six  months'  practice  is  necessary  to 
acquire  reasonably  satisfactory  proficiency. 

"As  the  result  of  thousands  of  observations  of  welds  produced  auto- 
matically (wherein  the  personal  equation  is  entirely  eliminated),  the  writer 
inclines  toward  the  theory  that  the  molten  electrode  material  passes  through 
the  arc  in  the  form  of  globules;  and  that  where  |-in.  electrode  material 
is  employed  with  a  current  of  about  150  amp.  these  globules  are  deposited 
at  the  rate  of  approximately  two  per  second.  The  passage  through  the 
arc  of  each  globule  apparently  constitutes  a  specific  cause  of  instability 
in  addition  to  those  existent  with  slowly  consumed  electrodes.  This 
hypothesis  seems  to  be  borne  out  by  ammeter  records,  typical  specimens 
of  which  appear  in  Fig.  177,  together  with  the  fact  that  the  electrode 


224 


ELECTRIC   WELDING 


fuses  at  the  rate  of  about  0.20  in.  per  see.  Moreover,  the  globules  appear 
to  be  approximately  equal  in  volume  to  a  piece  of  wire  0.125  in.  in 
diameter  and  0.10  in.  long. 

' '  Assuming  this  theory  to  be  correct,  to  maintain  a  uniform  arc  length 
in  manual  welding,  the  operator  must  feed  the  electrode  toward  the  work 


FiG.  177. — Typical   Ammeter  Charts   of   Operation   of  Morton   Automatic, 
Metallic-Electrode  Arc- Welding  Machine. 

Average  Time  about  1  Min.  45  Sec. 


at  the  rate  of  0.10  in.  upon  the  deposition  of  each  globule;  in  other  words, 
0.10  in.  twice  per  second,  a  synchronism  beyond  human  attainment. 
Simultaneously  with  such  feeding,  the  arc  must  be  moved  over  the  work 
to  melt  the  work  material,  distribute  the  molten  electrode  material,  and 
form  the  weld.  Inasmuch  as  the  effect  of  the  arc  is  highly  localized. 


AUTOMATIC  ARC  WELDING  225 

it  is  reasonable  to  suppose  that  different  parts  of  the  welding  area  present 
relatively  wide  variations  in  respect  to  temperature,  fluidity,  and  conduc- 
tivity of  the  molten  mass — controlling  factors  not  within  the  ken  of  the 
human  mind.  The  situation  is  further  complicated  by  the  facts  that 
neither  the  welding  wire  nor  the  work  material  is  uniform  in  fusibility 
or  in  conductivity,  and  that  the  contour  of  the  work  varies  continually 
as  its  surface  is  fused  and  the  molten  metal  is  caused  to  flow.  The  belief 
is  general  that  a  very  short  arc  is  productive  of  the  best  welding  results; 
but  it  is  an  arc  of  this  character  that  makes  the  greatest  demands  on 
the  skill  of  the  operator,  for  there  is  always  the  danger  that  the  electrode 
will  actually  contact  with  the  work  and  destroy  the  arc. 

''As  the  fusing  energy  of  the  arc  varies  widely  with  fluctuations  in 
the  arc  length  and  as  the  uniformity  of  the  weld  depends  on  the  constancy 
and  correctness  of  this  fusing  energy,  it  seems  remarkable  that  operators 
are  able  ever  to  acquire  such  a  degree  of  skill  as  to  enable  them  to  produce 
welds  that  are  even  commercially  satisfactory.  Further,  so  far  as  the 
writer  is  informed,  there  is  no  means,  other  than  such  as  would  be 
destructive,  for  determining  whether  a  completed  weld  is  good  or  bad. 
The  logical  solution  appeared  to  be  the  elimination  of  the  personal  equation 
and  the  substitution  therefor  of  means  whereby  tendencies  toward  variations 
in  the  arc  would  be  caused  automatically  to  correct  themselves,  just  as 
a  steam  engine,  through  the  action  of  its  governor,  is  caused  to  control 
its  own  speed. 

Methods  of  Mechanically  Stabilizing  and  Controlling  the  Arc. — Our 
efforts  for  a  number  of  years  have  been  directed  toward  stabilizing  and 
controlling  the  metallic  arc,  and  applying  such  stabilizing  and  controlling 
means  to  two  general  lines  of  welding  machinery:  (1)  Machines  for 
automatically  feeding  the  electrode  wire,  with  reference  to  the  work,  and 
producing  simultaneously  therewith  -relative  movement  between  the  wire 
and  the  work,  and  (2)  what,  for  lack  of  a  better  term,  might  be  called 
a  semi-automatic  machine,  in  which  the  feeding  of  the  electrode  and  the 
control  of  the  arc  are  accomplished  automatically  but  the  traversing  of 
the  electrode  with  reference  to  the  work  is  manually  effected  by  the  operator, 
permitting  him  the  exercise  of  judgment  with  reference  to  the  quantity 
of  metal  to  be  deposited  in  various  parts  of  the  groove.  The  automatic 
machine  has  been  in  successful  operation  for  a  long  period  and  the  semi- 
automatic machine  for  about  five  months.  While  the  goal  was  not  attained 
without  many  difficulties  and  a  great  expenditure  of  time  and  money,  the 
results  have  been  surprisingly  successful. 

' '  Because  of  the  lack  of  any  definite  data  as  to  what  actually  occurs 
in  this  form  of  arc,  or  why  it  occurs,  due,  no  doubt,  to  the  impossibility 
of  differentiating  between  phenomena  that  are  characteristic  of  the  arc 
and  phenomena  due  to  the  personal  equation  of  the  welder,  it  seemed 
logical  that  the  initial  step  should  be  to  so  environ  the  arc  that  it  would 
not  be  subject  to  erratic  extraneous  influences,  to  the  end  that  reasonably 
definite  determinations  might  be  substituted  for  scientific  speculation.  In 
the  design  and  construction  of  the  machines,  great  care  was  exercised 
to  minimize  the  possibility  of  mechanical  defects  that  might  lead  to 


226  ELECTRIC  WELDING 

erroneous  conclusions.  Starting  with  the  assumption  that  the  work  could 
only  be  based  on  open-minded  observation  of  the  behavior  of  the  arc 
under  machine  control,  an  automatic  welding  machine  was  built  in  which 
was  incorporated  the  greatest  possible  number  of  adjustable  features,  in 
order  that,  if  necessary,  it  might  be  possible  to  wander  far  afield  in  the 
investigations.  This  adjustability  has  proved  invaluable  in  that  it  has 
permitted  logical,  consistent,  and  sequential  experimenting  over  a  very 
wide  range  of  conditions.  Working  under  these  favorable  circumstances, 
there  were  soon  segregated  a  few  clearly  demonstrable  facts  to  serve  as 
a  foundation  for  the  structure,  which  has  since  been  added  to,  brick  by  brick, 
as  it  were. 

1 *  Efforts  have  been  directed  toward  the  practical  rather  than  the 
scientific  aspect  of  the  subject.  The  operation  of  the  automatic  machines 
has  brought  to  light  many  curious  and  interesting  phenomena,  some  of 
which  appear  to  negative  conclusions  heretofore  formed  which  have  been 
predicated  upon  observations  made  in  connection  with  manual  welding. 
It  is  hoped  that  these  and  other  phenomena,  which  can  thus  be  identified 
as  purely  arc  characteristics,  will  be  the  subject  of  profitable  scientific 
investigation  when  time  is  available  for  this  purpose. 

' '  In  the  five  forms  of  machines  made  in  the  course  of  the  development, 
the  welding  wire  is  automatically  fed  to  the  arc;  and,  in  the  first  four 
machines,  the  relative  movement  between  the  work  and  the  welding  wire 
is  automatically  and  simultaneously  effected.  Early  in  his  investigations, 
the  writer  concluded  that  a  substantial  equilibrium  must  be  maintained 
between  the  fusing  energy  of  the  arc  and  the  feeding  rate  of  the  welding 
strip;  and  it  soon  became  evident  that  if  the  welding  strip  is  mechanically 
fed  forward  at  a  uniform  rate  equal  to  the  average  rate  of  consumption 
with  the  selected  arc  energy,  this  equilibrium  is  actually  maintained  by 
the  arc  itself,  which  seems  to  have,  within  certain  circumscribed  limits, 
a  compensatory  action  as  follows:  When  the  arc  shortens,  the  resistance 
decreases  and  the  current  rises.  This  rise  in  current  causes  the  welding 
strip  to  fuse  more  rapidly  than  it  is  fed,  thereby  causing  the  arc  to  lengthen. 
Conversely,  when  the  arc  lengthens,  the  resistance  increases,  the  current 
falls,  the  welding  strip  is  fused  more  slowly  than  it  is  fed,  and  the  moving 
strip  restores  the  arc  to  its  normal  length. 

11  While  this  compensatory  action  of  the  arc  will  maintain  the  necessary 
equilibrium  between  the  fusing  energy  and  the  feeding  rate  under  very 
carefully  adjusted  conditions,  this  takes  place  only  within  relatively  narrow 
limits.  It  was  very  apparent  that,  due  to  variations  in  the  contour  of 
the  work,  and,  perhaps,  to  differences  in  the  fusibility  or  conductivity  of 
the  welding  strip  or  of  the  work,  the  range  of  this  self -compensatory  action 
of  the  arc  was  frequently  insufficient  to  prevent  either  contacting  of  the 
welding  strip  with  the  work  or  a  rupture  of  the  arc  due  to  its  becoming 
too  long.  The  problem  that  arose  was  to  devise  means  whereby  the  natural 
self-compensatory  action  of  the  arc  could  be  so  greatly  accentuated  as  to 
preclude,  within  wide  limits,  the  occurrence  of  marked  arc  abnormalities. 
There  was  ultimately  evolved,  by  experiment,  such  a  relation  between  the 
fusing  energy  of  the  arc  and  the  feeding  rate  of  the  welding  strip  as  to 


AUTOMATIC  ARC  WELDING 


227 


give  the  desired  arc  length  under  normal  conditions;  and  tendencies  toward 
abnormalities  in  arc  conditions,  no  matter  how  produced,  were  caused  to 


FIG.  178. — Piloted   Cup   Automatically   Welded   by   Metallic-Electrode   Arc 
Process  to  Tube  to  Form  75-MM.  Shrapnel  Shell. 

Analysis  of  Electrode  Material:  Silicon,  0.02  Per  Cent;  Sulphur,  0.013  Per  Cent; 
Phosphorus,  0.07  Per  Cent;  Manganese,  Trace;  Carbon,  0.07  Per  Cent;  Aluminum, 
0.038  Per  Cent. 


FIG.  179. — Piloted  Cup   Automatically  Welded  by  Metallic-Electrode  Arc 

Process  to  Tube  to  Form  75-MM.  Shrapnel  Shell. 

Analysis  of  Electrode  Material:  Silicon,  0.03  Per  Cent;  Sulphur,  0.049  Per  Cent; 
Phosphorus,   0.008   Per  Cent;    Manganese,   0.31   Per  Cent;    Carbon,   0.28   Per  Cent. 

bring  into  operation  compensatory  means  for  automatically,  progressively, 
and  correctively  varying  this  relation  between   fusing  energy  and  feeding 


228 


ELECTRIC  WELDING 


rate,  such  compensatory  means  being  under  the  control  of  a  dominant 
characteristic  of  the  arc.  In  their  ultimate  forms,  the  devices  for  effecting 
the  control  of  the  arc  are  simple  and  entirely  positive  in  action,  making 
discrepancies  between  fusing  energy  and  feeding  rate  self -compensatory 
throughout  widely  varying  welding  conditions.  For  instance,  the  shrapnel 
shell  shown  in  Fig.  178  was  automatically  welded  with  wire  differing 
greatly  in  chemical  constitution  from  that  used  on  the  shell  shown  in 
Fig.  179  (see  analyses),  yet  no  change  was  made  in  either  the  mechanical 
or  the  electrical  adjustments.  The  radically  different  welding  conditions 
were  compensated  for  solely  by  the  operation  of  the  automatic  control. 
The  electrode  materials  used  for  the  shells  shown  in  Figs.  180  and  181 


FIG.  180. — Piloted   Cup   Automatically   Welded   by   Metallic-Electrode    Arc 
Process  to  Tube  to  Form  75-MM.  Shrapnel  Shell 

Analysis  of  Electrode  Material:  Silicon,  0.02  Per  Cent;  Sulphur,  0.032  Per  Cent; 
Phosphorus,  0.008  Per  Cent;  Manganese,  0.20  Per  Cent;  Carbon,  0.18  Per  Cent. 

differed  so  greatly  from  those  employed  respectively  in  welding  the  shells 
shown  in  Figs.  178  and  179  that  a  change  in  the  relation  between  fusing 
energy  and  feeding  rate  had  to  be  made  manually.  After  this  adjustment 
was  made,  the  shells  were  welded  with  their  respective  electrodes,  which  varied 
widely  in  their  chemical  constitution,  without  further  manually  changing 
either  the  mechanical  or  the  electrical  conditions. 

"In  a  recent  test  of  the  semi-automatic  machine,  shown  in  Fig.  182, 
successful  welds  were  made  under  the  condition  that  the  impressed  voltage 
of  the  welding  generator  was  changed  throughout  a  range  of  from  50  to  65 
volts,  without  necessitating  any  manual  adjustment.  The  only  observable 
effects  of  the  wide  variations  in  the  supply  voltage  were  slight  differences 
in  the  arc  length.  In  short,  the  compensatory  action  of  the  control  has 
proved  effective  over  a  wide  range  of  welding  conditions,  not  only  as  to 


AUTOMATIC   ARC   WELDING  229 

the  electrical  supply  and  chemical  constitution  of  both  electrode  and  work 
materials,  but  also  as  to  extensive  variations  in  the  contour  of  the  work 
and  in  many  other  particulars.  This  makes  it  seem  apparent  that  the 
machines  do  not  represent  merely  successful  laboratory  experiments  but 
are  suited  to  the  requirements  of  actual  commercial  welding. 

"One  particularly  interesting  observation  resulting  from  the  experiments 
is  that  the  angle  of  inclination  of  the  electrode  with  reference  to  the  work 
is  very  important.  An  angular  variation  of  5  deg.  will  sometimes  determine 
the  difference  between  success  and  failure  in  a  weld.  About  15  deg.  from 
the  perpendicular  works  well  in  many  cases.  In  welding  some  materials, 
the  electrode  should  drag,  that  is,  point  toward  the  part  already  welded 
rather  than  toward  the  unwelded  part  of  the  seam. 


FlG.  181. — Piloted    Cup    Automatically   Welded   by   Metallic-Electrode    Arc 
Process  to  Tube  to  Form  75-MAI.  Shrapnel  Shell. 

Analysis  of  Electrode  Material:  Silicon,  0.04  Per  Cent;  Sulphur,  0.016  Per  Cent; 
Phosphorus,  O.OfiS  Per  Cent-  Manganese,  None;  Carbon,  0.24  Per  Cent. 

"While  it  has  been  customary  in  some  welding  systems  to  provide 
means  whereby  extra  resistance  is  inserted  in  series  with  the  arc  at  the 
instant  of  the  initial  contact  which  starts  the  flow  of  current,  the  resistance 
being  automatically  cut  out  upon  the  striking  of  the  arc,  experience  with 
the  automatic  machines  indicates  that  this  is  quite  unnecessary. 

"Early  in  the  experiments,  it  was  noted  that  in  many  cases  there  was 
a  decidedly  marked  affinity  between  particular  electrode  materials  and 
particular  work  materials.  A  slight  change  in  either  element  affects  the 
degree  of  this  affinity.  While  it  has  invariably  been  possible  to  contiol 
and  maintain  the  arc  and  weld  continuously,  in  some  instances  incom- 
patibility between  electrode  material  and  work  material  has  been  productive 
of  interesting  phenomena.  For  instance,  the  combination  of  work  material 
(steel  of  about  0.45  per  cent,  carbon  content)  and  the  particular  electrode 


230 


ELECTRIC   WELDING 


material  used  in  Fig.  178  produced  an  arc  that  was  remarkably  quiet  and 
free  from  sputtering.  Throughout  the  weld,  this  arc  was  suggestive  of 
the  quiet  flame  of  a  candle  or  lamp,  the  erratic  behavior  that  we  are 
accustomed  to  associate  with  the  ordinary  metallic  arc  being  absent.  The 
effect  is  reflected  in  the  uniform  deposition  of  the  welding  material. 

"On  some  classes  of  work  materia1  Bessemer  wire,  which  some  authorities 
claim  cannot  be  used  in  metallic-electrode  arc  welding,  produces  an  arc 


FIG.  182. — Morton  Semi-Automatic  Metallic-Electrode  Arc-Welding  Machine. 

The  Electrode  is  automatically  fed  to  the  arc,  which  is  automatically  maintained 
while  the  machine  is  manually  moved  along  the  groove  to  be  welded. 

and  a  weld  very  satisfactory  in  appearance.  On  other  work  material,  the 
Bessemer  wire  arc  is  violently  explosive.  These  explosions  are  accompanied 
by  quite  sharp  reports  and  the  scattering  over  some  considerable  distance 
of  globules  of  molten  metal  frequently  s/82  in.  or  more  in  diameter.  Under 
certain  other  conditions,  apparently  growing  out  of  incompatibility  between 
the  work  material  and  the  electrode  material,  the  oxygen  flame  accompany- 
ing the  arc  gyrates  very  rapidly  about  the  arc,  producing  an  effect  sug- 
gestive of  the  '  whirling  dervish. ' 


AUTOMATIC  ARC  WELDING  231 

"From  both  the  practical  and  the  scientific  points  of  view,  the  writer 
has  experimented  quite  extensively  with  varying  combinations  of  work 
material  and  electrode  material.  Throughout  all  the  differences  in  arc 
conditions,  many  of  which  palpably  accentuate  the  natural  inclination 
toward  instability,  the  control  has  so  operated  as  to  justify  the  expression 
'the  arc  persists.' 

"Generally  speaking,  the  Swedish  and  Norway  iron  wires  seem  to 
produce  more  quiet  arcs  and,  possibly,  a  more  uniform  deposition  of  electrode 
material,  than  do  wires  of  other  classes.  These  welds  may  perhaps  be 
found  to  be  slightly  more  ductile  than  those  made  with  wires  of  other 
chemical  composition.  On  the  other  hand,  these  soft  wires,  although  un- 
doubtedly of  relatively  high  fusibility,  do  not,  for  some  reason,  seem  to 
produce  an  arc  that  cuts  into  some  work  material  as  deeply  as  might  be 
desired,  nor  as  deeply  as  do  the  arcs  formed  with  certain  other  kinds  of 
wire.  Considered  from  every  angle,  the  writer  is  disposed  to  regard  the 
Roebling  welding  wire  as  the  best  he  has  thus  far  tested  for  use  on  mild 
steel.  The  wire  produces  a  reasonably  quiet  arc  which  seems  to  cut  into 
the  work  to  more  than  the  ordinary  depth,  while,  at  the  same  time,  the 
electrode  material  is  fused  with  more  than  average  rapidity — thus  increas- 
ing the  welding  rate. 

' '  While  scientists  will  no  doubt  ultimately  arrive  at  the  correct  hypothesis 
for  solving  the  problem  of  why  one  combination  of  electrode  material  and 
work  material  is  productive  of  better  results  than  can  be  obtained  with 
another  combination,  the  writer's  conclusion  is  that,  with  the  data  at 
present  available,  the  determinations  must  be  made  by  actual  experimenting 
— having  in  mind  the  qualities  desired  in  the  particular  weld,  such  as 
ductility,  tensile  strength,  elongation,  and  elastic  limit.  Inasmuch  as  it 
is  possible,  with  the  automatic  machine,  to  maintain  arc  uniformity  with 
practically  any  kind  of  electrode  material  and  to  produce  welds  which, 
under  low  magnification,  at  least,  appear  to  be  perfect,  and  which  respond 
favorably  to  ordinary  tests  such  as  bending,  cutting  and  filing,  it  is  reason- 
able to  conclude  that  proper  selection  of  electrode  material  will  be  productive 
of  perfect  welds  on  any  kind  of  work  material.  To  date,  no  steel  has  been 
tested  on  which  apparently  satisfactory  welds  could  not  be  made.  High- 
speed tungsten  steel  has  been  successfully  welded  to  cold-rolled  shafting, 
using  Bessemer  wire  as  electrode  material,  as  is  shown  in  Fig  183. 
Ordinary  steels  varying  in  carbon  content  from  perhaps  0.10  to  0.55  per 
cent,  have  been  welded  with  entire  success. 

"Because  of  the  fact  that  the  complete  welding  operation  has  been 
automatic  and  may  be  continued  for  a  considerable  length  of  time,  say 
5  min.,  an  exceptional  opportunity  has  been  afforded  for  close  concentration 
upon  the  study  of  the  appearance  of  the  arc.  What  seems  to  occur  is 
that  the  molten  metal  in  the  crater  is  in  a  state  of  violent  surging,  sug- 
gestive of  a  small  lake  lashed  by  a  terrific  storm.  The  waves  are  dashed 
against  the  sides  of  the  crater,  where  the  molten  metal  of  which  they 
are  composed  quickly  solidifies.  The  surgings  do  not  seem  to  synchronize 
with  nor  to  be  caused  by  the  falling  of  the  globules  of  molten  metal  into 
the  crater,  but  seem  rather  to  be  continuous.  They  give  the  impression 


232 


ELECTRIC  WELDING 


that  the  molten  metal  is  subjected  to  an  action  arising  from  the  disturbance 
of  some  powerful  force  associated  with  the  arc — such,  for  instance,  as 
might  result  from  the  violent  distortion  of  a  strong  magnetic  field.  Alto- 
gether, the  crater  phenomena  are  very  impressive;  and  the  writer  hopes 
ere  long  to  be  able  to  have  motion  pictures  made  which,  when  enlarged, 
should  not  only  afford  material  for  most  fascinating  study,  but  also  throw 
light  upon  some  of  the  mysterious  happenings  in  the  arc. 

So  far,  electrode  wires  I  in.  in  diameter  have  been  chiefly  used  in 
the  machines.  Successful  welds  have  been  made  with  current  values  ranging 
from  below  90  to  above  200  amp.,  at  impressed  voltages  of  40,  45,  50, 


FIG.  183. — Tungsten  High-Speed  Eing  Automatically  Welded  by  Metallic- 
Electrode  to  Cold-Kolled  Core  to  Form  Milling-Cutter  Blank. 

55,  60,  65  and  80.  Under  these  varying  conditions,  the  voltage  across 
the  arc  has  been  roughly  from  16  to  22.  The  machines  have  thus  far  been 
run  only  on  direct  current.  Inasmuch  as  it  is  possible,  by  electrical  and 
mechanical  adjustments,  to  establish  nearly  any  arc  length  that  may  be 
found  to  be  most  desirable  for  a  particular  class  of  work,  and  as  the 
control  system  will  maintain  substantially  that  arc  length  indefinitely,  the 
fully  automatic  type  of  machine  is  nearly  as  certain  in  operation  as  a  lathe, 
drilling  machine,  or  any  other  machine  tool. 

' '  The  tool  shown  in  Fig.  182  weighs  about  10£  Ib.  The  operator  draws 
the  tool  along  the  groove  to  be  welded  at  such  a  rate  as  will  result  in 
the  deposition  of  the  quantity  of  metal  required  to  satisfactorily  effect  the 
weld.  This  tool  is  intended  for  use  in  the  many  restricted  spaces  en- 


AUTOMATIC  ARC  WELDING  233 

countered  in  ship  welding,  which  would  be  relatively  inaccessible  to  a  fully 
automatic  machine.  In  its  use,  the  skill  required  by  the  operator  is  reduced 
to  a  minimum.  After  one  man  had  practised  with  the  welding  tool  for 
not  more  than  2  hr.,  the  opinion  was  expressed  that  it  would  require  six 
months  to  train  a  welder  to  such  a  degree  of  proficiency  as  to  enable  him 
to  make  a  weld  equally  good  in  appearance. 

"Mr.  Hobart,  says  'There  is  always  a  matter  of  a  0.10  in.  or  more 
between  the  end  of  the  welding  rod  and  the  work.'  While  undoubtedly 
it  is  difficult,  if  not  impossible,  to  maintain  in  manual  welding  an  arc 
shorter  than  this,  the  writer  has  frequently,  with  the  automatic  machines, 
made  continuous  and  strikingly  good  welds  with  arcs  of  much  less  length. 
In  fact,  in  some  cases  there  has  been  continuously  maintained  an  arc  so 
short  that  there  hardly  seemed  to  be  any  actual  separation.  The  writer 


FIG.  184. — No.  11  Gage  Steel  Tubing  Automatically  Welded  by  Metallic- 
Electrode  Arc  Process  at  the  Rate  of  One  Foot  per  Minute. 

has  even  wondered  whether,  under  these  conditions,  there  was  not  a  close 
approach  to  casting  with  a  continuous  stream  of  fluid  metal  acting  as  the 
current  conveyor  in  lieu  of  or  in  parallel  with  the  usually  assumed  vapor 
path.  The  work  that  has  been  done  indicates  that  under  automatic  control 
much  shorter  arcs  can  be  utilized  than  have  hitherto  been  deemed  possible, 
and  with  probable  marked  gain  in  quality  of  work  in  some  instances;  also, 
that  there  is  much  to  be  learned  as  to  the  mode  of  current  action  and 
current  conduction  in  such  an  arc. 

"With  the  automatic  machine,  black  drawing  steel  0.109  in.  thick 
has  been  welded  at  the  rate  of  22  in.  per  minute.  A  Detroit  manufacturer 
welded  manually  with  oxy-acetylene  at  the  rate  of  four  per  hour  a  large 
number  of  mine  floats  10  in.  in  diameter,  made  of  this  material.  The 
automatic  machine  made  the  welds  at  the  rate  of  forty  per  hour.  Liberty 


234 


ELECTRIC   WELDING 


motor  valve  cages  2|  in.  in  diameter  have  been  welded  to  cylinders  in 
36  sec.,  as  against  about  5  min.  required  for  manual  welding.  No.  11 
gage  steel  tubing,  shown  in  Fig.  184,  has  been  welded,  with  an  unnecessarily 


FIG.  185. — Two  i-in.  Ship  Plates  Automatically  Welded  by  Metallic- 
Electrode  Arc  Process  to  Form  Lap  Joint. 


FlG.  186. — Two  £-in.  Ship  Plates  Automatically  Welded  by  Metallic- 
Electrode  Process  to  Form  Butt  .Joint. 


heavy  deposit  of  metal,  at  the  rate  of  1  ft.  per  minute.  The  productive 
capacity  of  the  machines  so  far  made  has  been  from  three  to  ten  times 
that  of  manual  welding  methods,  depending  on  the  thickness  of  the  work 


AUTOMATIC  ARC   WELDING 


235 


material;  the  difference  in  favor  of  automatic  welding  varies  inversely 
as  such  thickness.  The  writer  is  now  designing  an  improved  type  of 
machine  for  use  especially  on  heavy  work,  with  which  machine  it  is  expected 
to  be  able  automatically  to  lapweld  £-in.  ship  plates,  in  the  manner  shown 
in  Fig.  185,  at  the  rate  of  15  ft.  per  hour.  One  of  the  largest  shipbuilding 
concerns  in  the  United  States  reports  that  the  general  average  of  all  its 
manual  welders  on  this  class  of  work  is  from  1  ft.  to  18  in.  per  hour. 
Other  specimens  of  automatic  welding  on  ship  plates  are  shown  in  Figs. 
186  and  187. 

* '  Bare  wire  only  has  been  used  in  the  automatic  machines ;  and  the 
results  obtained  seem  to  indicate  that  the  covering  of  the  electrodes  is  an 
expensive  superfluity.  If  the  chief  advantage  of  the  covered  electrode  lies 
in  the  ability  of  the  operator  to  maintain  a  very  short  arc,  an  arc  equally 
short  and  possibly  shorter  can  be  continuously  maintained  by  the  automatic 
machine  using  bare  electrodes. 

"No  attempt  has  thus  far  been  made  to  use  the  automatic  machines 


FIG.  187.— Two  i-in.  Ship  Plates  Automatically  Welded  by  Metallic-Elec- 
trode Arc  Process,  Showing  First  of  Three  Layers  to  Form  Lap  Joint. 

on  overhead  work.  The  welds  made  with  the  fully  automatic  machine  have 
been  of  three  kinds,  the  usual  longitudinal  form,  annular  about  a  horizontal 
axis,  and  annular  about  a  vertical  axis. 

"As  far  as  the  maintenance  of  arc  uniformity  and  the  apparent 
character  of  the  welds  are  concerned,  the  writer  has  repeatedly  welded 
with  wire  showing  evidence  of  pipes  and  seams,  as  well  as  with  rusty 
wire  and  with  wire  covered  with  dirt  and  grease.  In  this  connection  it 
may  be  said  that  no  pains  is  ever  taken  to  remove  rust,  scale,  or  slag 
from  the  work  material — even  where  welds  are  superimposed.  Apparently 
under  uniform  conditions  of  work  traverse,  arc  length,  and  electrode  angle 
of  inclination,  such  as  are  possible  in  the  automatic  machine,  impurities 
vanish  before  the  portion  of  the  work  on  which  they  occur  reaches  the 
welding  area  of  the  arc. 

"The  writer  is  fully  convinced  that  with  the  use  of  the  automatic 
machine,  ductility,  like  other  physical  properties  in  the  weld,  can  be  con- 
trolled "by  proper  selection  of  electrode  wire,  in  conjunction  with  electrical 


236 


ELECTRIC  WELDING 


AUTOMATIC   ARC   WELDING  237 

and  mechanical  adjustments  best  suited  to  the  particular  purpose  in  view. 
Automatic  welds  have  repeatedly  been  made  on  5/i6-in.  mild  steel  which, 
when  subjected  to  a  90-deg.  bend,  showed  a  marked  extrusion  of  the 
welded  material  but  no  sign  of  fracture.  When  the  welded  pieces  are 
cut  with  a  hacksaw,  it  is  very  unusual  to  be  able  to  note  any  difference 
in  cutting  qualities  between  the  unwelded  and  the  welded  parts. 

"While  the  automatic  machine  has  not  been  used  on  metal  less  than 
0.109  in.  thick,  it  is  fair  to  presume  that,  with  proper  adjustments,  entirely 
satisfactory  results  can  be  obtained  on  much  thinner  work — particularly 
if  the  nature  of  the  work  is  such  as  to  permit  of  the  use  of  a  chill.  The 
best  method  in  welding  very  light  metal  seems  to  be  to  use  a  small  electrode, 
a  relatively  low  current,  and  a  high  rate  of  work  traverse.  In  this  way 
welding  conditions  may  be  controlled  to  almost  any  desired  extent,  because 


FIG.  189. — How  the  Metal  Edges  Are  Welded. 

the  heating  action  of  the  arc  can  be  modified,  its  effect  intensely  localized, 
and  the  edges  to  be  welded  subjected  to  the  fusing  action  for  as  brief 
a  time  as  might  be  found  necessary  to  prevent  burning  of  the  metal. 
These  conditions,  which  seem  to  be  requisite  in  order  to  successfully  weld 
very  thin  material,  cannot  be  met  by  the  manual  welder.  It  is  here  that 
the  deficiencies  incident  to  the  personal  equation  become  most  apparent. 
A  very  slight  variation  in  arc  length  or  the  least  hesitancy  in  moving  the 
arc  over  the  work  will  almost  certainly  result  in  its  being  burned  through. 
In  short,  this  class  of  welding  calls  for  a  coordination  of  faculties  and  a 
delicacy  of  manipulation  beyond  the  capabilities  of  the  most  skillful  manual 
electric  welder.  Therefore  this  work  is  usually  done  with  the  oxy-acetylene 
flame,  wherein  fusing  conditions  arc  far  more  easily  controlled  than  is 
possible  in  manual  metallic  electrode  arc  welding." 

SHEET  METAL  ARC- WELDING  MACHINE 

The  machine  shown  in  Fig.  188  is  used  by  the  General 
Electric  Co.,  Schenectady,  N.  Y.,  for  arc-welding  corrugated 
steel  tank  work.  The  seams  are  116  in.  long,  and  the  arc 


238  ELECTRIC   WELDING 

is  applied  by  means  of  a  tapered  carbon  pencil  6  in.  long,  J 
in.  in  diameter  at  the  large  end  and  -J  in.  at  the  arc  end.  This 
concentrates  heat  where  wanted.  No  metal  is  supplied  to  the 
weld,  as  the  arc  is  employed  simply  to  fuse  the  upturned  edges 
as  shown  in  Fig.  189.  The  metal  welded  is  Vie  and  3/32  in- 
thick. 

The  speed  on  1/16-in  stock  is  51/2  in.  per  minute  with  a 
d.c.  current  of  45  amp.,  and  75  volts.  On  3/32-m.  stock  the 
speed  is  the  same  but  70  amp.  and  75  volts  d.c.  current  is 
used. 


CHAPTER   XII 
BUTT-WELDING    MACHINES    AND    WORK 

Aside  from,  arc-welding  machines,  which  have  already  been 
described,  electric  welding  machines  may  be  all  included  under 
one  head — Resistance  Welding  Machines.  These  may  be 
divided  into  butt-,  spot-,  seam-,  mash-  and  percussive-welding 
classes.  The  first  three  are  sometimes,  for  manufacturing  pur- 
poses, used  in  combinations  in  the  same  machine,  such  as  a 
spot-and-seam  machine  or  a  butt-and-spot-welding  machine, 
and  so  on.  This  does  not  mean  that  these  different  methods 
of  welding  are  carried  on  at  the  same  time,  but  that  a  welder 
can  do  work  on  the  same  machine  by  simply  shifting  the  work, 
or  a  part  of  the  fixture. 

In  butt-welding,  alternating  current,  single  phase,  of  any 
commercial  frequency  such  as  220,  440  or  550  volts,  60  cycles, 
is  commonly  used.  Lower  voltages  and  lower  frequencies  can 
be  used,  but  they  add  to  the  cost  of  the  machine.  The  machine 
can  be  used  on  one  phase  of  a  two-phase  or  a  three-phase 
system,  but  cannot  be  connected  to  more  than  one  phase  of 
a  three-phase  circuit.  Direct  current  is  not  used  because  there 
is  no  way  of  reducing  the  voltage  without  interposing  resist- 
ance, which  wastes  the  power.  As  an  example,  a  d.c.  plating 
dynamo  will  give  approximately  5  volts,  which  will  do  for 
certain  kinds  of  welding,  but  for  lighter  work,  less  current  is 
needed.  If  resistance  is  used  to  reduce  the  current  this  resist- 
ance is  using  up  power  just  as  if  it  were  doing  useful  work. 
The  voltage  at  the  weld  will  run  from  1  to  15  volts,  depending 
on  the  size  of  the  welder  and  work.  To  obtain  this  low  voltage, 
a  special  transformer  inside  the  machine  reduces  the  power 
line  voltage  down  to  the  amount  required  at  the  weld.  The 
transformer  is  placed  within  the  frame  of  the  machine,  as 
shown  in  Fig.  190.  The  secondary  winding  of  the  transformer 
is  connected  to  the  platens  by  means  of  flexible  copper  leads. 

239 


240 


ELECTRIC  WELDING 


From  the  platens  the  welding  current  travels  to  the  work 
clamps  and  through  them  to  the  pieces  to  be  welded.  As  the 
parts  to  be  welded  are  brought  into  contact  a  switch  is  thrown 
in  and  the  current  traveling  across  heats  the  ends  of  the  work 
and  when  the  proper  welding  heat  is  reached  the  operator 


WORK  STOP 


ClAMP  ADJUSTMENT 
CLAMP  JAW  WITH  STEEL  DIE 
I/COPPER  DIE 


CLAMP  RELEASE 
CLAMP  LOCKING 


Fie.  190.— Principal  Parts  of  a  Butt-Welding  Machine. 

pushes  the  two  parts  together  and  the  weld  is  completed.  Since 
the  current  value  rises  as  the  potential  falls  in  the  secondary 
circuit,  and  since  the  heating  effect  across  the  work  is  directly 
proportional  to  the  current  value  it  will  be  easily  seen  why 
a  transformer  is  necessary  to  produce  a  heavy  current  by  lower- 


BUTT-WELDING  MACHINES  AND  WORK 


241 


ing  the  line  potential.  Due  to  the  intermittent  character  of 
the  load,  there  is  no  standard  rating  for  welding  transformers, 
and  different  makers  frequently  give  entirely  different  ratings 
for  their  machines.  However,  regardless  of  the  rating  capacity 
in  kilowatts,  there  can  be  very  little  difference  in  the 
actual  amount  of  current  consumed  unless  an  especially  bad 


FIG.  191. — Butt-Welding  Machine  with  Work  in  Jaws. 

transformer  design  is  used.  To  heat  a  given  size  stock  to 
welding  temperature  in  a  given  time  requires  an  approximately 
invariable  amount  of  current. 

The  machine  just  illustrated,  is  shown  at  a  slightly  different 
angle  and  with  two  pieces  of  rod  in  the  jaws,  in  Fig.  191. 
This  is  the  Thomson  regular  No.  3,  butt-welding  machine.  It 


242 


ELECTRIC  WELDING 


FIG.  192.— Details  of  Foot-Operated  Clamping  Mechanism. 


PlG.  193. — A  Hand-Operated  Clamp. 


FIG.  194. — Toggle-Lever  Clamp  for  Bound  Stock. 


BUTT-WELDING   MACHINES  AND  WORK 


243 


has  a  capacity  of  rod  from  j  to  J  in.  in  diameter  or  flat  stock 
up  to  Y4X2  in.,  in  two  separate  pieces,  or  rings  of  Vie-in, 
stock  and  not  less  than  2  in.  in  diameter.  Hoops  and  bands 
up  to  Yi6Xl3/4  in.  and  not  less  than  9V2  *n-  diameter  when 
held  below  the  line  of  welding,  may  also  be  welded.  With 
jaws  specially  made  to  hold  the  work  above  the  line  of  welding 
a  minimum  diameter  of  4£  in.  is  necessary.  This  machine  will 
produce  from  150  to  200  separate  pieces,  150  to  300  hoops, 
or  300  to  400  rings  per  hour.  The  lower  dies  are  of  hard 
drawn  copper  with  contact  surfaces  lVsX2  in.X2V16  in.  thick. 


FIG.  '195. — Clamping  Device  for  Heavy  Flat  Stock. 

Standard  transformer  windings  are  for  220,  440  and  550  volts, 
60  cycle  current.  Current  variation  for  different  sizes  of  stock 
is  effected  through  a  five-point  switch  shown  at  the  left. 
Standard  ratings  are  15  kw.  or  22  kva.,  with  60  per  cent  power 
factor.  The  dies  are  air  cooled  but  the  clamps  to  which  the 
dies  are  bolted  are  water  cooled.  This  type  of  machine  occupies 
a  floor  space  40X33  in.,  and  is  53  in.  high.  The  weight  is 
1,750  Ib.  A  close-up  view  of  the  treadle-operated  clamping 
.•jaw  mechanism  is  given  in  Fig.  192. 

The  method  of  operating  the  clamping  jaws  differs  accord- 


244 


ELECTRIC   WELDING 


ing  to  the  size  of  the  machine  and  the  work  that  is  to  be 
done.  On  some  of  the  smaller  machines  the  type  of  hand- 
operated  clamp  shown  in  Fig.  193  is  used.  On  other  machines, 
intended  to  handle  round  stock  principally,  the  toggle  lever 
clamp  shown  in  Fig.  194  is  used.  For  very  heavy  flat  stock, 
the  hand-lever  clamping  mechanism,  shown  in  Fig.  195,  is 
used.  On  some  of  the  machines  used  on  small  repetition  work 
the  clamps  and  switch  are  automatically  cam-operated  as  shown 
in  Figs.  196  and  197.  The  first  machine  is  a  bench  type  used 


FIG.  196. — A  Cam-Operated  Machine. 

for  welding  on  twist  drill  shanks,  and  the  second  machine  is 
used  for  welding  harness  rings.  These  jobs  are,  of  course, 
merely  examples  as  the  machines  are  adapted  for  all  sorts 
of  the  smaller  welding  jobs.  Spring  pressure,  toggle-lever  or 
hydraulic  pressure  arc  used  to  give  the  final  "shove-up"  accord- 
ing to  the  machine  used  or  weight  of  stock  being  welded. 

In  welding  hard  steel  wire  of  over  35  per  cent  carbon 
content,  it  is  necessary  to  anneal  the  work  for  a  distance  of 
about  1  in.  on  each  side  of  the  wold.  This  is  due  to  the  fact 


BUTT-WELDING   MACHINES  AND  WORK 


245 


that  the  wire  on  each  side  is  rendered  brittle  by  the  cooling 
effect  of  the  clamping  jaws.  To  accomplish  this  annealing, 
all  the  small  Thomson  machines  used  for  this  work  are  equipped 
with  a  set  of  V-jaws  outside  of  the  clamping  jaws,  as  shown 
in  front  in  Fig.  198.  The  wire  is  laid  in  these  V's  with  the 


FIG.  197. — Automatic-Operated  Machine  Welding  Harness  Rings. 

weld  half  way  between  and  the  current  is  thrown  on  intermit- 
tently by  means  of  a  push  button  until  the  wire  has  become 
heated  to  the  desired  color,  when  it  is  removed  and  allowed 
to  cool.  The  annealing  of  a  small  drill  is  shown  in  Fig.  199. 
The  process  of  welding  and  annealing  12  gage,  hard  steel  wire, 


246 


ELECTRIC  WELDING 


FIG.  198. — Machine  Equipped  with  Annealing  Device. 


FIG.  199. — Annealing  a  Small  Drill. 


BUTT-WELDING   MACHINES  AND  WORK  247 

requires  about  30  sec.  when  done  by  an  experienced  operator. 
Copper  and  brass  wire  are  easily  welded  in  these  same  machines. 
The  machine  shown  will  weld  iron  and  steel  wire  from  No. 
21  B.  &  S.  to  J  in.  in  diameter  and  flat  stock  up  to  No.  25 
B.  &  S.Xi  in.  wide.  Production  is  from  150  to  250  welds  per 
hour,  the  actual  welding  time  being  1|  sec.  on  J-in.  steel  wire. 
The  clamps  are  spring-pressure,  with  adjustable  tension 
released  by  hand  lever.  The  standard  windings  are  furnished 
for  110,  220,  440  and  550  volts,  60  cycles.  Five  variations  are 
made  possible  by  the  switch.  The  ratings  are  1£  kw.  or  3 
kva.,  with  60  per  cent  power  factor.  The  weight  is  120  pounds. 

For  use  in  wire  mills  where  it  is  desired  to  weld  a  new 
reel  of  wire  to  the  end  of  a  run-out  reel  on  the  twisting  or 
braiding  machines,  it  has  been  found  convenient  to  mount  the 
machine  on  a  truck  or.  small  bench  on  large  casters.  This 
enables  one  to  move  the  welder  from  one  winding  machine  to 
another  very  easily,  to  splice  on  new  reels  of  small  wire,  the 
electrical  connection  to  the  welder  being  made  by  flexible  cord, 
which  is  plugged  into  taps  arranged  at  convenient  points  near 
each  winding  machine.  It  is  also  desirable  to  mount  on  this 
same  bench  a  small  vise  in  which  to  grip  the  wire  to  file  off 
the  burr  resulting  from  the  push-up  of  the  metal  in  the  weld. 
The  average  time  required  to  weld,  anneal  and  file  up  a  16-gage 
steel  wire  with  this  bench  arrangement  is  only  about  one 
minute.  The  only  preparation  necessary  for  welding  wire  is 
that  the  stock  be  clean  and  the  ends  be  filed  fairly  square  so 
that  they  will  not  push  by  one  another  when  the  pressure 
is  applied. 

In  connection  with  welding  wires  and  rods  up  to  J  in. 
in  diameter,  Table  XX  will  be  found  very  handy.  For  sizes 
from  J  to  2J  in.  the  reader  is  referred  to  Table  XXVI. 

Examples  of  Butt- Welding  Jobs. — while,  as  a  rule,  it  is 
only  necessary  to  have  clean  and  fairly  square  ends  for  butt- 
welding  in  some  cases  where  small  welding  is  to  be  done  it 
has  been  found  best  to  bevel  or  V  the  abutting  ends.  This  is 
more  apt  to  be  the  case  with  non-ferrous  metals,  however,  than 
with  iron  or  steel.  A  notable  example  in  the  larger  work  is 
in  the  scarfing  of  the  ends  of  boiler  tubes  when  butt-welding 
is  done.  This  phase  of  the  question  has  apparently  not  been 
given  the  attention  it  deserves,  and  some  cases  where  welding 


248 


ELECTRIC   WELDING 


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BUTT-WELDING   MACHINES  AND   WORK 


249 


lias  been  declared  a  failure  in  manufacturing  may  be  laid 
to  the  fact  that  the  parts  to  be  welded  were  not  scarfed  and 
consequently  would  not  stand  the  required  tests  after  being 
welded.  As  a  general  rule,  a  properly  executed  butt-weld 
should,  when  reduced  to  the  size  of  the  original  section,  have 
practically  the  same  strength. 

Although  copper  and  brass  rod  and  strip  can  be  welded 


FIG.  200. — Typical  Copper  Welds. 

with  perfect  success,  owing  to  the  nature  of  the  metal  it 
requires  a  specially  constructed  machine  to  secure  the  best 
results.  Since  copper  has  a  very  low  specific  resistance  as 
compared  to  iron  or  steel,  it  requires  much  more  current  to 
melt  it  on  a  given  size  rod.  A  longer  time  is  required  also 
to  heat  a  given  size  of  rod  as  compared  to  steel,  but  when 


FlG.  201. — Welded  Aluminum  Ring. 

the  plastic  stage  is  reached  the  metal  flows  so  rapidly  that  it 
must  be  pushed  up  with  tremendous  speed  or  the  molten 
copper  will  flow  out  between  the  abutting  ends.  To  effect  this 
rapid  push-up  of  stock  the  platen  on  which  the  movable  right- 
hand  clamp  is  mounted  must  move  very  freely  indeed,  neces- 
sitating roller  bearings  on  the  larger  sizes  of  machines.  The 


250 


ELECTRIC  WELDING 


pressure  spring  on  the  smaller  machines  must  also  be  capable 
of  maintaining  its  tension  through  a  longer  distance  than  on 


Fia.  202.— A  Steel  Wire  Weld. 


FIG.  203. — Welded  Hoisting  Drum  Crank  Forging. 


FiO.  204.— Large  Welded  Pinion  Blank. 

a  machine  for  iron  and  steel,  since  more  metal  is  pushed  up 

on  a  given  size  of  copper  rod  than  would  be  on  steel  or  iron. 

The  properties  of  brass  and  also  aluminum  are  practically 


BUTT-WKLDLNG  MACHINES  AND  WORK  251 


FIG.  205. — Welding  a  Band  Saw. 


FIG.  206. — Bandsaw  Weld  before  and  after  Removing  Flash. 


252  ELECTIC  WELDING 

the  same  as  those  of  copper  and  therefore  this  special  type 
of  machine  is  just  as  well  adapted  for  these  metals. 

Typical  copper  welds  are  shown  in  Fig.  200.  The  one  at 
the  left  shows  it  just  as  it  came  from  the  machine,  and  the 
one  at  the  right  with  the  flash  partly  removed.  Fig.  201 
shows  an  aluminum  ring  immediately  after  welding.  A  steel 
wire  weld  is  shown  in  Fig.  202,  and  a  welded  hoisting  drum 
crank  in  Fig.  203.  This  last  illustration  shows  how  some 
drop  forgings  may  be  simplified  and  the  cost  of  dies  and 
production  lessened.  A  large  pinion  gear  blank  is  shown  in 
Fig.  204.  Made  in  this  way,  a  large  amount  of  time  and  metal 
is  saved.  The  way  to  weld  pieces  of  large  and  small  cross 
section  is  described  in  the  article  on  tool  welding. 

Band  saws  may  be  butt-welded  as  shown  in  Fig.  205.  The 
way  a  band  saw  looks  after  welding  and  after  the  flash  is 
removed  is  shown  in  Fig.  206. 


T-WELDING 

T-welding,  which  is  a  special  form  of  butt-welding,  is,  as 
its  name  implies,  the  process  of  making  a  weld  in  the  shape 
of  the  letter  "T".  Where  it  is  desired  to  weld  a  piece  of 
iron  to  the  middle  of  another  bar  of  equal  size  or  larger,  it 
becomes  necessary  to  heat  the  top  bar  of  the  "T"  to  a  bright 
red;  then  bring  the  lower  bar  to  the  preheated  one  and  again 
turn  on  the  current,  when  a  weld  can  quickly  be  made.  The 
reason  for  doing  this  is  as  follows:  The  pieces  are  of  unequal 
area  in  cross-section  at  the  junction  of  the  two  pieces.  As 
it  takes  longer  to  heat  the  upper  part,  the  end  of  the  lower 
part  of  the  "T"  would  burn  before  the  upper  piece  would 
reach  the  welding  temperature.  Preheating  will  equalize  and 
overcome  this  difficulty.  Special  machines  known  as  "T" 
welders  are  built  for  this  class  of  work  to  facilitate  the  pre- 
heating, when  the  highest  possible  production  on  this  form 
of  weld  is  desired. 

Automobile  Rim  Work. — One  of  the  largest  applications  of 
butt- welding  today  is  to  be  found  in  the  automobile-rim  in- 
dustry. The  special  form  of  clamp  shown  in  Fig.  195  was 
especially  designed  to  handle  rims  of  all  kinds  and  sizes.  It 
is  not  adaptable  for  any  type  of  work  other  than  flat  stock, 


BUTT-WELDING   MACHINES  AND   WORK  253 

as  the  amount  of  jaw-opening  is  much  smaller  than  the  diameter 
of  equivalent  section  of  round  stock. 

No  backing-up  stops  of  any  kind  are  built  for  these  machines 
with  rim-clamps,  as  stops  are  unnecessary  for  this  class  of 
work.  In  order  to  secure  sufficient  gripping  effect  of  the  stock 
to  prevent  it  slipping  in  the  clamp- jaws,  the  upper  dies  are 
made  of  self-hardening  steel  with  the  gripping  surface  cor- 
rugated. The  lower  dies,  which  carry  all  the  current  to  the 
work,  are  made  of  copper  with  Tobin-bronze  shoes  on  which 
the  work  rests,  so  as  to  give  good  conductivity  and  yet  present 
a  hard  wearing  surface  to  the  steel  rim.  These  lower  dies 
must  not  only  bear  the  gripping  effort  exerted  by  the  steel 
dies  above,  but  also  the  weight  of  the  rim,  which,  in  large  sizes, 
amounts  to  considerable. 

The  method  employed  in  welding  automobile  rims  is  the 
"flash-weld"  principle,  wherein  the  current  is  first  turned  on 
with  the  edges  to  be  welded  pulled  apart.  The  pressure  is 
then  applied  gently  to  bring  the  abutting  ends  slowly  together. 
As  uneven  projections  come  into  contact  across  from  opposite 
edges  they  are  burned  or  "flashed"  off,  which  is  evidenced 
by  flying  particles  of  burning  iron.  The  pressure  is  gradually 
increased,  bringing  more  of  the  length  of  the  opposite  edges 
into  contact  and  when  the  "flash"  throws  out  for  the  full 
width  of  the  rim  which  indicates  the  abutting  ends  are  touch- 
ing all  the  way  across,  the  final  pressure  is  quickly  applied 
as  the  current  is  turned  off,  thereby  completing  the  weld.  It 
has  been  found  that  experienced  operators  on  this  kind  of 
work  do  not  look  at  the  weld  itself  but  govern  their  actions 
by  the  appearance  of  the  amount  of  flash  or  sparks  thrown 
out.  When  this  assumes  the  shape  of  a  complete  fan  they  know 
it  is  the  right  moment  to  cut  off  the  current  and  apply  the 
final  pressure. 

The  burr  or  fin  thrown  up  in  this  type  of  weld  is  very 
short  and  very  brittle,  making  its  removal  much  easier  than 
would  be  the  case  with  the  heavy  burr  resulting  from  a  slow 
butt-weld.  It  is  the  common  practice  in  rim  plants  to  remove 
the  burr  while  it  is  still  hot  and  with  a  pneumatic  chisel  or 
a  sprue  cutter.  The  slight  amount  of  burr  then  remaining 
is  ground  off  with  a  coarse  abrasive  wheel  and  the  rim  is  ready 
for  the  forming  process.  In  most  rim  plants  the  operations 


254 


ELECTRIC  WELDING 


of  rolling,  welding,  chiseling  burr,  grinding  burr,  forming, 
shaping,  etc.,  fit  in  so  closely  to  one  another  that  a  rim  is 
practically  kept  moving  continuously  from  the  time  the  flat 
stock  is  put  into  the  rolls  until  a  finished  rim  emerges.  The 
welding  operation  itself  on  a  rim  blank  for  30X3|  tire  size, 
for  instance,  has  an  average  production  rate  of  60  rims  per 
hour,  some'  concerns  doing  even  better  than  this.  On  large 


FIG.  207. — Truck  Rim  "Welding  Machine. 

truck  rims  for  solid  tires,  having  a  section  of  16  Xf  in.  thick, 
a  production  of  10  rims  per  hour  is  considered  very  good, 
although  there  are  concerns  doing  even  better  than  this  on 
such  heavy  work. 

The  machine  shown  in  Fig.  207  was  specially  designed  for 
handling  heavy  truck  rims  only.  The  lower  jaws  on  this 
welder  are  placed  very  low  in  order  that  the  machine  can 


BUTT-WELDING  MACHINES  AND  WORK  255 

be  set  in  a  comparatively  shallow  pit  to  bring  the  line  of 
weld  on  a  level  with  the  floor.  This  makes  it  possible,  with 
proper  tracking  arrangements,  to  roll  heavy  rims  right  onto 
the  lower  dies  without  any  lifting,  the  rim  being  rolled  out 
again  after  welding.  The  double  oil-transformers  used  in  this 
welder  hang  below  the  base  line,  which  necessitates  a  small 
pit  directly  under  the  center  of  machine.  Owing  to  this  and 
also  the  weight  to  be  supported,  a  concrete  foundation  only 
should  be  employed. 

This  machine  has  a  capacity  for  stock  |X8  to  |X16  in., 
or  a  maximum  thickness  of  1  in.  with  a  cross-sectional  area 
of  not  over  7  sq.  in.  Rims  with  a  minimum  diameter  of  30  in. 
can  be  welded.  The  pressure  is  effected  by  twin  hydraulic 


FIG.  208. — A  Heavy  Welded  Eim. 

cylinders  operated  from  an  external  accumulator  giving  a 
maximum  pressure  of  24  to  37  tons  on  the  work.  The  voltage 
windings  are  of  the  same  capacity  as  for  other  machines.  The 
transformer  is  of  the  oil  cooled  type,  and  the  ratings  are  160 
kw.  or  266  kva.,  with  60  per  cent  power  factor.  Primary 
windings  of  transformers  are  submerged  in  cooling  oil  con- 
tained in  casings.  Platens  on  which  the  clamps  are  mounted 
and  the  bodies  of  the  lower  jaws  to  which  the  contact  shoes 
are  bolted,  are  water  cooled.  This  machine  is  66X101  in.  and 
66  in.  high.  The  net  weight  is  14,000  pounds. 

A  heavy  rim  after  welding  is  shown  in  Fig.  208. 

Welding  Pipe. — In  order  to  weld  pipe  and  tubing  in  the 
form  of  coils  for  condenser  systems  cooling  tubes,  heating 
coils,  etc.,  as  shown  in  Fig.  209,  it  was  found  necessary  to 


256  ELECTRIC  WELDING 

employ  a  special  form  of  clamp  wherein  the  jaws  could  be 
set  up  high  to  give  clearance  above  the  pressure-device.  The 
thickness  of  the  die  and  die-block  to  which  it  is  bolted  also 
had  to  be  reduced  to  a  minimum  so  as  to  insert  the  jaws 
between  coils,  since  the  pipe  is  coiled  through  each  length  and 
then  another  length  is  welded  on,  which  in  turn  is  coiled,  and 
so  on.  In  order  to  secure  the  best  gripping  effect  with  a 
comparatively  light  die,  it  is  necessary  to  make  this  form  of 
die  considerably  longer  than  those  used  in  the  other  types 


FIG.  209.— Welding  Pipe  Coils. 

of  horizontal-acting  clamps.  Moreover,  since  there  is  not 
enough  space  in.  the  narrow  block  to  which  the  die  is  bolted 
to  permit  water  circulation,  the  die  itself  must  be  water-cooled 
to  prevent  softening  of  the  copper  from  continued  contact  with 
the  hot  pipe  just  in  back  of  the  weld. 

This  type  of  clamp,  Fig.  210,  is  designed  for  welding  of 
pipe  and  tubing  only,  which  requires  a  much  lighter  pressure 
to  push  up  than  solid  stock  of  the  same  cross-sectional  area, 
and  since  the  line  of  weld  is  considerably  above  the  line  of 
pressure,  the  slides  will  be  quickly  worn  on  the  movable  platen 
if  heavy  pressure  is  used  continually.  For  this  reason  the 


BUTT-WELDING  MACHINES  AND  WORK  257 


FIG.  210. — Clamp  Used  for  Pipe  Welding. 


Fie.  211.— Winfield  Portable  Butt-Welding  Machine. 


258 


ELECTRIC  WELDING 


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BUTT-WELDING   MACHINES  AND  WORK 


259 


welding  of  any  solid  stock  with  this  class  of  machine  is  not 
advisable. 

The  machine  shown  will  weld  iron  and  steel  pipe  from  f 
to  2  in.  in  diameter,  ordinary  pipe  sizes  and  1J  in.  extra  heavy 
pipe,  or  double  heavy  1  in.  in  diameter.  Standard  steel  tubing 


FIG.  212. — A  General  Purpose  Butt- Welding  Machine. 

from  1  to  2J  in.  diameter  may  be  welded.    Pressure  is  supplied 
by  a  hydraulic  oil  jack  exerting  a  maximum  of  5  tons.     The 
standard  ratings  are  30  kw.  or  50  kva.,  with  power  factor  of 
60  per  cent.    The  machine  will  weigh  about  2,500  pounds. 
For   welding   pipe,    Table   XXI   will   be   found   useful   for 


260  ELECTRIC  WELDING 

reference  purposes.  This  table  was  compiled  by  the  Thomson 
Electric  Welding  Co.,  with  special  reference  to  their  machines. 

Winfield  Butt-Welding  Machines.— The  Winfield  Electric 
Welding  Machine  Co.,  Winfield,  Ohio,  makes  a  complete  line 
of  butt-welding  machines  but  only  a  few  representative  of 
their  line,  will  be  shown.  A  very  convenient  portable  or  bench 
type  is  shown  in  Fig.  211.  This  is  especially  useful  for  light 
manufacturing  work.  It  has  a  capacity  of  18  to  6  gage  wire. 
It  is  equipped  with  a  1  kw.  transformer,  hand  clamping  levers 
and  a  3-step  self-contained  regulator  for  controlling  the  cur- 
rent. It  occupies  a  floor  space  of  13^X16  in.,  is  35  in.  high 
from  floor  to  center  of  welding  dies,  and  weighs  about  130  Ib. 
complete. 

The  machine  shown  in  Fig.  212  is  for  general  all-round 
shop  work.  It  has  a  capacity  of  from  j  to  1  in.  round,  or 
gX2  in.  flat  stock.  It  has  a  25-kw.  transformer,  water-cooled 
welding  jaws,  enclosed  non-automatic  switch  on  upsetting  lever, 
stop  for  regulating  amount  of  take-up  on  each  weld,  ten-step 
self-contained  regulator  for  controlling  the  current,  occupies 
a  floor  space  of  44X25  in.,  is  42  in.  high  to  center  of  jaws  and 
weighs  about  1,800  Ib.  The  jaws  overhang  as  shown,  for 
welding  hoops,  rings,  rims,  etc. 

The  machine  shown  in  Fig.  213  is  for  toolroom  work  and 
was  especially  designed  for  handling  large  cross-sections.  It 
will  weld  up  to  2-|  in.  round.  All  clamping  and  upsetting 
operations  are  accomplished  by  means  of  air  or  hydraulic  pres- 
sure. The  clamping  cylinders  are  operated  independently  of 
each  other  by  means  of  separate  valves,  which  enable  the 
operator  to  clamp  each  piece  before  the  current  is  turned  on. 
The  small  air  cylinder  on  the  right-hand  end  of  the  machine 
keeps  the  work  in  close  contact  during  the  heating  operation. 
The  final  pressure  is  applied  by  the  hydraulic  ram  after  the 
proper  welding  heat  has  been  attained.  The  table  at  the  left 
is  equipped  with  adjustments  for  moving  it  up  or  down,  back 
and  forth,  tilting  or  twisting.  This  feature  is  especially  valu- 
able in  experimental  work  and  often  saves  buying  a  special 
machine  for  unusual  manufacturing  jobs.  The  terminals  are 
cooled  by  a  stream  of  water  which  flows  from  one  to  the  other. 
The  dies  are  held  in  place  by  slotted  clamps  which  permit  easy 
removal.  Work  stops  and  stops  to  regulate  the  amount  of 


BUTT-WELDING   MACHINES   AND   WORK 


261 


upset  are  provided.  The  movable  table  is  fitted  with  roller 
bearings  to  insure  easy  operation.  The  transformer  is  a  Win- 
field  125  kw.  The  machine  has  a  ten-step  current  regulator, 
and  the  current  for  welding  is  controlled  by  a  Cutler-Hammer 
magnetic  switch  which  in  turn  is  operated  by  means  of  a 
small  auxiliary  switch  placed  on  the  valve  lever  controlling 
the  hydraulic  ram.  The  floor  space  occupied  is  60X90  in.,  and 
the  approximate  weight,  ready  for  shipment,  is  8,000  Ib. 


FIG.  213. — Winfield  Toolroom  Machine. 

Table  XXII  compiled  by  this  concern  contains  some  useful 
data  not  given  in  the  other  tables. 

Federal  Butt- Welding  Machines.— The  machines  built  by 
the  Federal  Machine  and  Welder  Co.,  Warren,  Ohio,  do  not 
differ  in  the  principles  of  operation  from  the  machines  already 
described.  The  form  of  the  one  shown  in  Fig.  214,  however, 
differs  considerably  from  any  shown.  The  tables,  or  platens, 
are  flat  and  are  T-slotted  so  that  various  fixtures  may  be  easily 
bolted  in  place.  The  maximum  capacity  for  continuous  service, 
is  2J  in.  round  or  other  shape  of  equal  section.  Flats  up  to 


262 


ELECTRIC   WELDING 


§X10  in.  may  be  welded.  The  platens  are  of  gunmctal  and 
the  T-slots  will  take  J-in.  bolts.  These  platens  are  recessed  and 
water-cooled.  Pressure  is  applied  by  means  of  an  hydraulic 
jack,  shown  at  the  right.  The  switch  is  remote  control  mag- 
netically operated.  The  main  switch  is  controlled  by  a  small 
shunt  switcli  which  is  worked  either  by  hand  or  foot,  as  desired. 
The  transformer  is  100  kva.  It  has  an  eight-step  regulating 
coil.  Floor  space  occupied  is  38X88  in.,  height  50  in.,  weight 
5,600  Ib.  This  machine  is  intended  to  weld  auto-rims,  heavy 
forgings,  steel  frames,  shafting,  high-speed  steel  and  work 


FIG.  214. — Federal   Heavy-Duty   Butt- Weld  ing   Machine. 

requiring  accurate  alignment  and  rapid  production  in  quan- 
tities. 

A  set  consisting  of  a  tube  welder  and  roller  is  shown 
in  Fig.  215.  This  will  weld  tubes  from  1J  to  3  in.  It  will 
also  weld  flat,  round  or  square  stock  of  equivalent  cross  section. 
The  dies  are  water-cooled,  and  the  work  is  clamped  in  position 
by  air  cylinders  operating  on  a  line  pressure  of  80  to  100  Ib. 
The  switch  is  on  the  main  operating  lever,  so  that  the  heat 
is  at  all  times  under  the  control  of  the  operator.  The  trans- 
former is  65  kw.  air  cooled.  Eight  current  steps  are  obtained. 
The  machine  occupies  a  floor  space  of  30X51  in.,  is  42  in.  high, 
and  weighs  2,100  Ib.  By  using  the  set,  a  tube  may  be  welded 
and  immediately  transferred  to  the  rolling  machine  and  the 


BUTT-WELDING   MACHINES  AND   WORK 


263 


TABLE  XXII. — COST  OF   J  TO  2   IN.   WELDS   PER   THOUSAND 


Area  in 

Time  • 

Cost  Per 

Average 

Labor 
Cost 

Diameter 
of  Stock 

Square 
Inches 

K.  W. 

Required 

Horse 
Power 

in  Sec.      1000  Welds 
Per          at  1  c.  Per 
Weld      K.W.  Hour 

No.          Per  JOOO 
of  Welds      at  30c. 
Per  Hour  Per  Hour 

y4     Inch 

.05 

2 

3 

3 

.02 

400 

.75 

5  /             I  ( 

.08 

3 

4 

4.5 

.05 

375 

.80 

3/          a 

.11 

4 

5 

6 

.07 

350 

.85 

Vw       " 

.15 

5 

7 

6.5 

.10 

300 

1.00 

.20 

6 

8 

7 

.12 

250 

1.20 

Vie      '  ' 

.25 

7 

9 

7.5 

.15 

200 

1.50 

5A     " 

.31 

8 

11 

8 

.18 

150 

2.00 

.37 

9 

12 

9 

.23 

130 

2.30 

3/r  " 

.44 

10 

13 

10 

.28 

100 

3.00 

13  /             <  < 

.52 

10.5 

14 

12 

.35 

95 

3.20 

jA6  ;| 

.60 

11 

15 

15 

.46 

90 

3.30 

.69 

11.5 

15.5 

17 

.55 

85 

3.50 

i  3  " 

.79 

12 

16 

18 

.60 

80 

3.70 

r/s    " 

.99 

16 

21 

20 

.89 

75 

4.00 

iy!   ;; 

1.23 

19 

25 

25 

1.32 

70 

4.30 

1.48 

25 

33 

30 

2.08 

65 

4.60 

1  V2     '  ' 

1.77 

31 

41 

35 

3.00 

60 

5.00 

i5A    " 

2.07 

38 

51 

37 

3.90 

55 

5.50 

i3/     " 

2.41 

45 

60 

40 

5.00 

48 

6.20 

1  7  /             <  < 

2.76 

53 

71 

43 

6.34 

40 

7.50 

2          '  ' 

3.14 

60 

80 

45 

7.50 

30 

10.00 

flash  rolled  out.     The  time  consumed  in  rolling  down  the  flash 
on  a  2|-in.  tube  is  given  as  approximately  20  seconds. 


FIG.  215. — A  Tube-Welding  Set. 

Welding  Rotor  Bars  to  End  Rings. — In  the  General  Electric 
Review  for  December,  1918,  E.  F.  Collins  and  W.  Jacob  describe 


264  ELECTRIC  WELDING 

the  welding  of  rotor  bars  to  the  end  rings  used  in  squirrel-cage 
induction  motors,  employing  the  machine  shown  in  Fig.  216. 
This  machine  has  a  double  set  of  welding  jaws,  the  front  set 
being  used  to  butt-weld  end  rings  to  make  them  seamless, 
while  the  rear  set  is  used  to  weld  the  rotor  bars  to  the  end 
rings.  As  shown,  the  machine  is  welding  rotor-bars  to  the 
end-rings.  The  description  of  the  work  as  carried  out  in  the 
General  Electric  shops  is  as  follows : 

"The  projecting  rotor  bars  surround  a  toothed  end  ring, 


FlG.  216 — General  Electric  Machine  for  Eotor  Work. 

which  is  of  slightly  smaller  diameter  than  the  rotor.  A  small 
block  of  copper  is  placed  so  that  it  covers  the  copper  end 
surfaces  of  a  rotor  bar  and  the  corresponding  tooth  on  the 
end  ring,  after  which  it  is  butt-welded  into  place. 

The  projecting  rotor  bars  are  shown  at  A  in  Fig.  217  and 
the  toothed  end  ring  just  inside  the  circle  of  rotor  bars  is 
shown  at  B.  Finished  welds  as  at  C  show  blocks  in  place. 
The  actual  operation  is  as  follows:  A  rotor  bar  is  tightly 
clamped  to  the  corresponding  tooth  of  the  end-ring  between 
the  jaws  D  and  E,  The  copper-block  end-connection  is  placed 


BUTT-WELDING   MACHINES  AND  WORK 


265 


so  that  it  covers  the  combined  area  of  tooth  and  bar  ends. 
The  movable  jaw  F  holds  the  end  connection  in  place,  and 
heavy  pressure  is  then  applied  through  compression  springs. 
The  welding  current,  furnished  by  a  special  transformer  having 
a  one-turn  secondary,  passes  from  jaw  F  through  the  surfaces 
and  out  through  jaw  E.  This  heavy  current  at  low  voltage 
causes  intense  heating  due  to  the  comparatively  high  resistance 


FlG.  217. — Details  of  the  Welding  Mechanism  and  Work. 

at  the  surface  junction,  and  raises  the  temperature  of  the 
copper  to  welding  heat,  at  which  point  the  metal  is  plastic. 

At  this  stage  spring  pressure  forces  the  jaw  F  toward  the 
rotor  and  squeezes  out  any  oxide  which  may  have  formed 
between  the  welding  surfaces.  A  small  stream  of  water,  play- 
ing upon  the  hot  area,  forms  an  atmosphere  of  super-heated 
steam  which  prevents  the  formation  of  oxide  and  also  guards 
against  excessive  heating  of  the  copper.  No  flux  is  used  in 
the  operation  as  the  mechanical  squeezing-out  of  the  oxide 


266  ELECTRIC   WELDING 

is  sufficient  to  form  a  homogeneous  connection  between  the  two 
surfaces. 

As  the  welding  jaws  approach  one  another  when  the  metal 
becomes  plastic,  an  electrical  connection  is  automatically  made 
which  operates  a  solenoid-controlled  switch  that  opens  the 
primary  transformer  circuit.  Thus  the  current  is  interrupted 
as  soon  as  the  surfaces  have  knitted  together.  The  contacts 
of  this  automatic  switch  are  placed  one  on  each  movable  jaw, 
and  are  so  adjusted  that  they  are  separated  by  the  distance 
necessary  for  the  jaws  to  approach  one  another  in  forming 


FIG.  218. — Butt- Welding  the  End  Eings. 

the  weld  and  in  forcing  out  the  oxide.  In  this  way,  the  end 
connection  is  butt- welded  to  the  rotor  bar  and  the  end  ring, 
forming  a  junction  of  great  mechanical  strength  and  low 
resistance. 

Another  example  of  non-ferrous  butt  welding  is  the  making 
of  seamless  end  rings,  which  operation  is  performed  in  the 
same  machine.  The  operation  is  shown  in  detail  in  Fig.  218, 
which  shows  a  finished  end  ring  in  place.  One  end  of  the 
ring  is  placed  in  the  vise-jaws  G  and  H,  and  the  other  is  held 
in  the  opposite  jaws  /  and  J.  As  the  jaws  approach  pressure 
is  applied  by  means  of  the  springs.  In  all  other  respects  the 
operation  is  similar  to  that  of  welding  the  end  connections. 


BUTT-WELDING   MACHINES  AND   WORK 


267 


Rotors  up  to  14  ft.  in  diameter  are  welded  and  Fig.  219 
shows  the  rotor  for  a  1,400-hp.  motor  being  welded. 

The  work  is  done  rapidly;  for  example,  end  connections 
with  a  welding  surface  of  about  0.6  by  0.4  in.  are  welded  at 
the  rate  of  about  90  an  hour. 

Welding  Brass. — Brass  rotor  bars  and  end  rings  are  also 
butt-welded  in  a  similar  manner,  but  the  operation  is  slower. 
Brass,  being  an  alloy,  has  a  lower  melting  point  than  copper, 


FIG.  219. — Welding  End  Eing  and  Kotor  Bars  for  1400-H.P.  Motor. 

and  less  pressure  is  necessary  to  effect  a  weld.  The  pressure 
is  determined  by  the  thickness  of  the  piece  to  be  welded,  and 
should  be  just  enough  to  form  a  small  " flash"  at  the  point 
of  union.  Excessive  pressure  will  cause  the  molten  metal  to 
spurt  out  from  the  point  of  weld.  In  one  fundamental 
particular  the  butt-welding  of  brass  differs  from  that  of  copper, 
the  pressure  on  brass  must  not  be  released  after  the  stoppage 
of  current  until  the  metal  has  hardened  sufficiently  so  that  it 
will  not  crack  on  cooling.  This  delay  retards  the  rate  of 
welding  to  the  extent  that  about  60  brass  end  connections. 


268 


ELECTRIC  WELDING 


of  the  size  previously  mentioned,  require  the  same  time  as 
90  of  copper. 

Butt-welding  has  been  the  means  of  producing  a  rotor  hav- 
ing low  resistance,  high  mechanical  strength,  and  ability  to 
permanently  withstand  vibration  and  centrifugal  force  without 
excessive  heating,  all  of  which  are  essential  factors  in  an 
efficiently  operated  squirrel-cage  induction  motor. 

WELDING  ELBOWS  ON  LIBERTY  CYLINDERS 

In  making  Liberty  motors  in  the  Ford  shop,  the  valve 
elbows  were  butt-welded  on  as  shown  in  Fig.  220.  The  holding 


FlG.  220. — Welding  Valve  Elbows. 

fixture  is  shown  with  the  hinged  top  thrown  back  and  a 
cylinder  in  the  cradle.  One  elbow  has  already  been  welded 
on,  and  the  other  is  held  in  the  jaws  of  the  sliding  fixture, 
ready  to  be  welded  in  place.  This  work  was  done  before 
the  cylinders  were  finish  bored  and  by  so  doing  all  cylinder 
distortion,  due  to  welding  was  cut  out  in  the  finish  boring. 

An  automatic  straight-link  chain  making  machine,  built  by 
the  Automatic  Machine  Co.,  Bridgeport,  Conn.,  is  shown  in 


BUTT-WELDING   MACHINES   AND   WORK 


269 


Fig.  221.  This  machine  took  the  material  from  a  reel,  shown 
at  the  right,  formed  it,  butt-welded  the  ends  of  the  links  and 
turned  out  the  chain  as  indicated.  The  machine  was  so  made 
that  the  welded  part  of  each  link  was  pressed  between  special 
dies  while  still  hot,  the  operation  practically  eliminating  the 


FIG.  221. — Automatic  Chain  Making  Machine. 

flash  formed  in  welding.    Aside  from  the  welding  features,  the 
machine  was  a  marvel  of  mechanical  ingenuity  and  simplicity. 

ELECTRO-PERCUSSIVE  WELDING 

The  joining  of  small  aluminum  wires  has  always  presented 
much  difficulty  on  account  of  the  oxide  film  which  prevents 
the  metal  parts  from  flowing  together,  unless  brought  to  a 
point  of  fluidity  at  which  the  oxide  film  can  be  broken  up 
and  washed  away.  If  this  be  attempted  with  small  sections, 
the  whole  mass  is  likely  to  be  oxidized,  and  the  resulting  joint 
will  be  brittle  or  "crumbly." 

In  1905  L.  "W.  Chubb,  of  the  Westinghouse  Electric  and 
Manufacturing  Co.,  Pittsburgh,  Penn.,  discovered  that  if  two 


270 


ELECTRIC  WELDING 


pieces  of  wire  were  connected  to  the  terminals  of  a  charged 
condenser,  and  then  brought  together  with  some  force,  that 
enough  electrical  energy  would  be  concentrated  at  the  point 


FlO.  222. — Electro-Percussive  Welding  Machine. 

of  contact  to  melt  the  wires,  while  the  force  of  the  blow 
would  weld  them  together.  Accordingly,  a  welding  process 
was  developed  and  used  by  the  Westinghouse  company,  and 


BUTT-WELDING   MACHINES   AND   WORK 


271 


machines  made  which  are  capable  of  welding  all  kinds  of  wire 
up  to  No.  13  gage.    The  process  was  called  electro-percussive 


FIG.  223. — Details  of  Percussive  Welding  Machine   and  Wiring  Diagram. 

welding  and  a  machine  for  doing  the  work  is  shown  in  Fig. 
222.    This  machine  has  vertical  guides  A  between  which  travels 


272  ELECTRIC  WELDING 

a  chuck  B  holding  one  wire  C.  The  other  wire  is  held  below 
in  chuck  D  in  such  a  position  that  the  end  of  the  moving  wire 
strikes  it  squarely.  Each  chuck  is  connected  by  flexible  cable 
to  a  circuit  as  shown  in  Fig.  223.  An  electrolyte  condenser 
A,  shown  in  the  wiring  diagram,  is  connected  across  a  source 
of  direct  current  from  B,  which  charges  it  to  a  potential 
determined  by  the  resistances  C  and  D.  A  switch  E 
keeps  the  chucks  F  and  G  at  the  same  potential  during  place- 
ment and  removal  of  work. 

After  the  wires  to  be  welded  have  been  chucked,  they  are 
clipped  short  by  a  cutter  which  gives  each  a  chisel,  or  wedge- 
shaped  end.  These  ends  are  set  at  right  angles  to  each  other. 
The  switch  is  opened  and  the  sliding  chuck  is  released  and 
allowed  to  fall.  At  the  instant  when  the  two  narrow  edges 
come  into  contact,  the  current  discharged  generates  intense 
heat  at  the  center  of  the  section.  The  metal  melts  and  is 
forced  out  by  the  impact  and  eventually  the  entire  surface 
of  each  wire  is  melted.  Due  to  the  very  large  body  of  cold 
metal  adjacent,  the  thin  film  of  molten  metal  solidifies  quickly 
and  since  it  is  under  momentarily  heavy  pressure  it  forms  a 
homogenous  mass  absolutely  continuous  with  the  wires  on 
each  side.  In  practical  operation,  the  inductance  H  is  required 
to  lower  the  rate  at  which  the  condenser  discharges,  that  is, 
to  maintain  the  current  at  a  lower  rate  until  the  entire  surface 
of  the  weld  has  been  forced  into  contact.  The  correct  action 
can  be  told  by  the  sound  made  by  the  contact.  It  should  be 
a  splash  or  thud,  rather  than  a  sharp  crack.  The  mass  and 
drop  of  the  falling  part  must  be  great  enough  to  slightly  forge 
the  material.  Once  set  for  the  proper  drop,  the  machine  will 
make  a  perfect  weld  every  time. 

Actual  tests  on  two  No.  18  B.  &  S.  aluminum  wires,  using 
an  oscillograph,  show  that  the  power  being  expended  at  the 
weld  reaches  a  value  of  23  kw.  for  an  instant.  However,  the 
entire  weld  is  made  in  0.0012  sec.,  and  the  total  energy  used 
at  the  weld  is  0.00000123  kw.-hr.  The  cost  of  this  weld,  figured 
at  10  cents  per  kw.-hr.,  would  be  twelve  millionths  of  a  cent. 

A  chart  of  the  oscillograph  aluminum-wire  test  just  referred 
to,  is  shown  in  Fig.  224.  At  A  the  right-angled  chisel-ends 
are  shown  almost  in  contact  as  the  upper  chuck  falls.  As  the 
ends  contact  at  B  the  voltage  drops  as  indicated  by  the  curve 


BUTT-WELDING  MACHINES  AND  WORK 


273 


G,  but  the  current  and  power  consumption  suddenly  increases 
as  shown  by  the  curves  H  and  /  respectively. 

At  C  the  wire  ends  have  separated,  caused  by  the  melting 
and  vaporizing  of  the  chisel  edges.  At  D  the  chucks  are  closer 
together  but  the  arc  is  still  burning  away  the  wire  ends.  At 
E  the  second  contact  has  been  made,  the  arc  eliminated  and 
upsetting  begun.  At  F  the  weld  is  shown  completed. 

One  of  the  principal  uses  for  this  process  is  in  welding 
copper  to  aluminum,  as  for  example  copper  lead-wires  to 


I 

BCD  E  F 

FIG.  224.— Chart  of  Oscillograph  Test  on  18  B.  &  S.  Gage  Aluminum  Wire, 
Showing  Power  Consumed  and  Time  to  Complete  a  Percussive  Weld. 

aluminum  coils.  The  advantage  of  copper  for  connecting  is 
self-evident,  as  it  is  easily  soldered.  It  was  thought  at  first 
that  a  weld  of  the  two  metals  would  result  in  a  brittle  joint, 
but  tests  show  that  after  several  years  the  joint  is  apparently 
as  strong  and  ductile  as  when  first  made.  Similar  ductility 
has  been  noted  in  almost  every  combination  of  metals  when 
first  welded,  but  disintegration  and  loss  of  ductility  eventually 
result  in  such  welds  as  silver  to  tin  or  aluminum  to  tin,  the 
welds  being  affected  by  what  is  known  as  "tin  disease "  or 
"tin  pest" — a  disintegration  of  the  molecules. 


274 


ELECTRIC  WELDING 


Alloy  of  practically  any  composition  can  be  welded  to  each 
other,  and  there  is  little  diffusion  of  one  metal  into  the  other 
across  the  welded  surface.  Thus  this  method  is  quite  suitable 


f?C 


FIG.  225. — Copper  Welded  to  Aluminum. 


for  attacking  contact  points  to  flat  plates  and  making  small 
welds  required  by  jewelers. 

Another  important  quality  of  the  process  is  that  metals 
which  soften  with  heating,  such  as  hard-drawn  copper  and 


BUTT-WELDING   MACHINES  AND  WORK  275 

silver,  can  be  welded  without  change  of  condition  since  the 
length  of  metal  heated  to  an  annealing  temperature  will  not 
be  more  than  0.004  in.  long  and  this  amount  of  metal  is  neg- 
ligibly small.  As  will  be  seen  from  the  specimens  in  Fig.  225, 
which  show  copper  welded  to  aluminum,  then  drawn  and  rolled, 
there  is  no  loss  of  ductility  at  the  weld  and  no  tendency  for 
the  two  metals  to  separate. 


CHAPTER   XIII 
SPOT- WELDING  MACHINES  AND  WORK 

Spot  welding,  as  the  name  indicates,  is  simply  welding  in 
spots.  Two  or  more  overlapping  metal  plates  or  sheets  may 
be  welded  together  at  intervals,  by  confining  electric  current 
to  a  small  area  of  passage  by  means  of  suitable  electrodes, 
or  "dies"  which  are  pressed  against  the  metal  from  opposite 
sides.  Spot  welding  is  a  form  of  resistance  welding.  Due  to 
the  way  the  metal  is  heated  and  forced  together  no  oxidizing 
takes  place,  and  in  consequence  no  flux  of  any  kind  is  needed. 

While  the  process  of  spot  welding  is  more  commonly  used 
at  present  for  welding  thin  sheet  iron,  steel  or  brass  articles, 
practical  machines  have  been  made  for  welding  two  pieces 
of  J-in.  ship  plate  together.  Experimental  machines  have  also 
been  made  capable  of  spot-welding  three  1-in.  plates  together, 
and  which  can  exert  a  pressure  of  36  tons  and  have  a  current 
capacity  of  100,000  amperes. 

To  weld  soft  cold-rolled  steel  in  a  satisfactory  commercial 
manner,  three  conditions  should  be  observed,  if  possible: 

First,  the  surfaces  to  be  welded  should  be  free  from  rust, 
scale  or  dirt.  If  the  work  is  not  clean  a  higher  secondary 
voltage  will  be  required  to  penetrate  through  the  scale  or  dirt 
of  any  given  thickness  of  sheet.  This  means  that  a  larger 
machine  and  more  current  must  be  used  than  would  be  required 
for  clean  stock  of  the  same  thickness. 

Second,  the  sheets  should  be  flat  and  in  good  contact  at 
the  spots  to  be  welded,  so  that  no  great  pressure  is  required 
to  flatten  down  bulges  or  dents. 

Third,  the  stock  should  not  surround  the  lower  horn,  as 
in  the  case  of  welding  the  side  seam  of  a  can  or  pipe. 

It  must  not  be  understood  that  spot  welding  cannot  be  done 
except  under  the  conditions  outlined,  for  it  can,  but  if  the 
conditions  named  are  not  followed  the  cost  of  welding  will 
be  greater.  However,  it  is  often  necessary  to  violate  these 

276 


SPOT-WELDING   MACHINES  AND  WORK  277 

conditions  in  actual  manufacturing  work.  This  is  especially 
true  of  the  third  one.  Where  the  lower  horn  must  be  sur- 
rounded by  the  work,  as  in  welding  can  seams,  the  capacity 
of  the  machine  is  cut  down  because  of  the  "induction  effect'7 
which  tends  to  choke  back  the  main  current  arid  in  this  way 
cuts  down  the  heating  effect  at  the  die  points.  This  so-called 
induction  effect  is  only  present  when  welding  steel  or  iron, 
no  such  action  being  noticeable  in  welding  brass. 

Light  gages  of  sheet  metal  can  be  welded  to  heavy  gages 
or  to  solid  bars  of  steel  if  the  light-gage  metal  is  not  greater 
than  the  rated  single  sheet  capacity  of  the  machine.  Soft  steel 
and  iron  form  the  best  welding  material  in  sheet  metals,  al- 
though it  is  possible  to  weld  sheet  iron  or  steel  to  malleable-iron 
castings  of  a  good  quality. 

Galvanized  iron  can  also  be  welded  successfully,  although 
it  takes  a  slightly  longer  time  than  clear  iron  or  steel  stock, 
in  order  to  burn  off  the  zinc  coating  before  the  weld  can  be 
made.  Contrary  to  common  opinion,  the  metal  at  the  point 
of  weld  is  not  made  susceptible  to  rust  by  this  burning  off 
of  zinc,  since  by  some  electrochemical  action  it  has  been  found 
that  the  spots  directly  under  each  die-point  and  also  around 
the  point  of  weld  between  the  sheets,  are  covered  with  a  thin 
coating  of  zinc  oxide  after  the  weld  has  taken  place.  This 
coating  acts  as  a  rust  preventive  to  a  very  noticeable  degree. 
On  spot-welded  articles  used  in  practice  for  some  time,  such 
as  galvanized  road-culverts,  refrigerator-racks  and  pans,  rain- 
gutters,  etc.,  it  has  been  found  that  no  trace  of  rust  has  ap- 
peared on  the  spot-welds  from  their  exposure  to  ordinary 
atmospheric  conditions.  Extra  light  gages  of  galvanized  iron 
below  28  B.  &  S.  gage  cannot  be  very  successfully  welded,  due 
to  the  fact  that  so  little  of  the  iron  is  left  after  the  zinc  has 
been  burnt  off  that  the  metal  is  very  apt  to  burn  through 
and  leave  a  hole  in  the  sheets. 

Tinned  sheet  iron  is  ideal  for  welding,  giving  great  strength 
at  the  weld,  but  the  stock  will  be  discolored  over  the  area 
covered  by  the  die-points.  Sheet  brass  can  be  welded  to  brass 
or  steel  if  it  contains  not  more  than  60  per  cent  copper.  It 
is  not  practical  to  attempt  to  spot-weld  any  bronze  or  alloy 
containing  a  higher  percentage  of  copper  than  this  as  the  weld 
will  be  weak. 


278 


ELECTRIC   WELDING 


Another  class  of  work  that  can  be  successfully  handled  on 
a  spot-welding  machine,  although  it  is  not  strictly  spot  welding, 
is  the  construction  of  wire-goods  articles.  This  consists  prin- 
cipally in  "mash- welding"  crossed  wires.  It  may  be  done 
with  the  same  copper  die-points  as  are  used  for  ordinary  spot 
welding,  except  that  the  points  are  usually  grooved  to  hold 
the  wire  in  the  required  position.  Among  the  common  wire 
goods  put  together  in  this  way  are  lamp-shade  frames,  oven 


FIG.  226. — Typical  Construction  of  Light  Spot-Welding  Machine. 

racks,  dish  drainers,  waste  baskets,  frames  for  floral  make-ups 
and  so  on.  Certain  classes  of  butt-welding  may  also  be  done 
on  a  spot-welding  machine  by  using  special  attachments. 

Details  of  Standard  Spot- Welding  Machines. — Spot-welding 
machines  are  made  in  various  sizes  and  designs  to  meet  dif- 
ferent requirements,  but  the  general  principle  of  action  is  the 
same  in  all.  The  illustration,  Fig.  226,  shows  a  Thomson  No. 
124-A10  machine  with  the  cover  removed.  This  gives  an  idea 
of  the  principal  mechanism  of  all  this  line  of  light  spot-welding 


SPOT-WELDING   MACHINES  AND  WORK 


279 


machines.  Fig.  227  shows  a  typical  head  of  one  of  their  line 
of  heavier  machines.  This  type  of  machine  is  designed  for 
heavy  work  on  flat  sheets  or  pieces,  where  considerable  pres- 
sure is  required  to  bring  the  parts  together  to  be  welded.  To 
withstand  heavy  pressures,  the  lower  horn  is  made  of  T-section 
cast  iron  and  the  current  is  conducted  to  the  lower  copper 
die-holder  by  flexible  copper  laminations,  protected  on  all  sizes 


SWITCH  ON  COMPRESSION   LEVER  TO  BE  U5EO  WHEN  AUTOMATIC 
SWITCH  IS  CUT  OUT  ff  MOPE  THAN  500  LB5.  15  OE5IRED 


COMPRESSION  LEVER  REMAINS  IN  UPPER 
POSITION  WHEN  U5ING  FOOT  TREADLE 


COMPRESSION  LEVER  COUNTER 
•""•"      6ALANCE  WEIGHT 


10  POINT  SELF  CON- 
TAINED REGULATOR 


TOGGLE  LINK  COMPRESSION 
5WIVEL   HEAD 


PIN  IN  THIS  SLOT  CUTS 
OUT  AUTOMATIC  SWITCH 


PIN  FOR  FASTENING  HEAD 
ff  FOOT  TREADLE  TOGETHER. 


AUTOMATIC  SOLENOID  CONTROL  SWITCH  -~ 

5CREW  REGULATING  AMOUNT - 
OF  TIME  CURRENT  IS  ON 

DIE  BLOCKS  SLIDE  IN  &•  OUT  -'"\ 
PRESSURE  ADJUSTABLE  SPRINGS  50-500  LB5  - 

WATER  COOLED  SWIVEL  DIE  >'' 
HEADS  WITH   INSERT  POINTS 


FIG.  227. — Spot-Welding  Machine  for  Heavy  Work,  with  Parts  Named. 

having  over  15-in.  throat,  by  a  brass  cover,  insulated  on  the 
inside  from  the  copper  by  a  coating  of  asbestos  sheet. 

The  sliding  head  of  the  machine  which  carries  the  upper 
die-holder  is  a  hollow  steel  plunger,  sliding  in  a  cast-iron  head, 
which  bolts  to  the  body  of  the  machine  and  on  which  arc 
mounted  the  control-switches.  The  pressure  is  applied  by  a 
toggle-motion  above  the  plunger,  actuated  both  by  a  swiveled 
hand-lever  on  top  of  the  head,  which  may  be  swung  into  any 


280  ELECTRIC  WELDING 

position  through  an  arc  of  260  deg.,  and  a  foot-treadle  at  the 
base,  which  also  may  be  swung  in  an  arc  of  30  deg.  This 
enables  the  operator  to  control  the  machine  by  hand  or  foot 
from  any  position  around  the  front  of  the  machine. 

The  current-control  can  be  set  to  work  automatically  with 
the  downward  stroke  of  the  upper  die.  In  this  case  the  pres- 
sure at  the  die-point  is  through  an  adjustable  spring-cushion 
in  the  hollow  cylinder-head.  The  current  is  automatically 
turned  on  after  the  die-points  have  come  together  on  the  work 
by  further  downward  pressure  of  either  lever.  With  the  ap- 
plication of  final  pressure,  to  squeeze  out  any  burnt  metal  as 
the  weld  is  forced  together,  the  current  is  automatically  turned 
off.  When  working  on  pieces  where  more  pressure  is  required 
to  bring  the  parts  together  before  welding  than  can  be  effected 
by  the  spring-cushion  without  turning  on  the  current,  it  is 
possible  to  set  a  plug  in  the  head  of  the  machine  so  that 
direct  connection  is  obtained  from  the  hand-lever  to  the  upper 
die-point  while  the  foot-treadle  still  operates  through  the 
spring-cushion  and  with  the  automatic  current-control.  When 
it  is  desired  to  secure  maximum  pressure,  the  plug  in  the 
head  can  be  set  again  so  that  both  the  hand-lever  and  the 
foot-treadle  give  direct  connection  to  the  die-point,  the  current 
being  controlled  by  a  push-buttom  on  the  outer  end  of  the 
hand-lever. 

The  regular  line  of  spot-welding  machines  of  different 
makes,  operate  on  110-,  220-,  440-  and  550-volt,  alternating  cur- 
rent. A  welding  machine  of  this  kind  can  only  be  connected 
to  one  phase  of  an  a.c.  circuit.  The  transformer  must  be  made 
to  furnish  a  large  volume  of  current,  at  a  low  voltage,  to  the 
electrodes.  For  further  transformer  details,  the  reader  is 
referred  to  the  article  on  butt-welding. 

The  Thomson  Foot-,  Automatic-,  and  Hand-Operated 
Machines. — The  machine  shown  in  Fig.  228  is  representative 
of  the  Thomson  line  of  small,  foot-operated  spot-welding 
machines.  These  are  intended  for  use  on  light  stock  where 
but  little  pressure  is  required.  The  die-holders  are  water- 
cooled,  arid  the  lower  horn  bracket  allows  the  horn  to  be 
adjusted  up  or  down  for  the  use  of  various  kinds  of  holders. 
The  automatic  switch  and  adjustable  throw-in  stop  are  plainlv 
shown  at  the  back  of  the  machine. 


SPOT-WELDING   MACHINES   AND   WORK 


281 


The  model  is  made  in  several  sizes.  The  first  size  will  weld 
from  30  to  16  B.  &  S.  gage  galvanized  iron  or  soft  steel,  or 
to  24  gage  brass.  It  will  mash-weld  wire  from  14  gage  to 
£  in.  in  diameter.  Its  throat  depth  is  12  in.;  the  lower  horn 
drop  clearance  is  9  in.;  size  is  22X45X51  in.  high;  net  weight 


FIG.  228. — The  Thomson  Light  Manufacturing  Type  Spot-Welding 

Machine. 

is  825  lb. ;  full  load  rating  is  5  kw.,  or  8  kva.  The  largest 
machine  of  this  particular  series,  will  weld  26  to  7  gage,  B. 
&  S.,  galvanized  iron  or  soft  steel,  or  18  gage  brass;  it  will 
mash-weld  10-gage  to  f -in.  diameter  wire ;  has  an  18-in.  depth 
of  throat;  is  28X60X56  in.  high;  weighs  1,550  lb.  and  full 
load  rating  is  15  kw.  or  25  kva. 


282 


ELECTRIC   WELDING 


On  repetition  work,  where  the  operator  has  to  work  the 
foot-treadle  in  rapid  succession  for  long  periods,  it  is  very 
tiresome.  For  such  work,  power-driven  machines  similar  to 
the  one  shown  in  Fig.  229  are  made.  These  machines  are  sup- 
plied either  with  individual  motor  drive  or  pulley  drive,  as 
desired.  The  control  is  effected  through  the  small  treadle 
shown.  The  regular  foot-treadle  is  used  while  setting  up  dies, 


FIG.  229. — The  Thomson  Semi- Automatic  Type  Spot-Welding  Machine. 

etc.  If  the  operator  desires  to  make  but  one  stroke,  he  depresses 
the  shorter  treadle  and  immediately  releases  it,  whereupon  the 
machine  performs  one  cycle  of  operation,  automatically  turn- 
ing on  the  current,  applying  the  pressure,  turning  off  the 
current,  and  stopping.  A  \-  to  -J-hp.  operating  motor  is  used 
according  to  the  size  of  the  machine.  Otherwise  the  capacity 
of  the  various  sizes  is  the  same  as  in  the  regular  foot-operated 


SPOT-WELDMG   MACHINES   AND  WORK  283 


FIG.  230. — A  Thomson  Heavy-Duty  Spot- Wei  ding  Machine. 


FIG.  231.— Spot- Welding  a  Sheet  Steel  Box, 


284 


ELECTRIC  WELDING 


machines.     The  lower  horn  and  upper  arm  may  be  of  either 
style  illustrated. 

The  machine  shown  in  Fig.  230  is  a  hand-lever  operated 
machine,  although  supplied  with  a  foot-treadle  which  can  be 


FIG.  232. — Showing  How  the  Horn  and  Welding  Points  May  Be  Set. 

swung  back  out  of  the  way  when  not  needed.  This  machine 
is  typical  of  the  Thomson  designs  used  for  the  heavier  run 
of  commercial  work.  On  the  various  sizes,  the  capacity  for 
spot-welding  is  from  22  B.  &  S.  gage  galvanized  iron  or  steel 


FlG.  233. — Welding  Small  Hoe  Blades  to  the  Shanks. 

up  to  No.  0  gage,  or  to  14  gage  brass.  Mash-welds  may  be 
made  on  from  -J-  to  f-in.  diameter  wire.  The  throat  capacities 
run  from  15  to  51  in.  and  the  lower  horn  adjustment  is  from 
12  to  24  in.  The  smallest  size  is  28X62X75  in.  high  and  the 


SPOT-WELDING  MACHINES  AND  WORK  285 


FiG.  234. — Welding  Stove  Pipe  Dampers. 


FlG.  2b5. — Mash- Welding  Lamp  Shade  Frames. 


286 


ELECTRIC  WELDING 


FlG.  236. — Butt-Welding  Attachment  for  a  Spot- Welding  Machine. 


FlG.  237.— Welding  Galvanized  Iron  Pipe. 


SPOT-WELDING   MACHINES  AND  WORK 


287 


largest  size  28X98X75  in.  high.  The  weights  run  from  2,335 
to  3,225  and  the  full  load  ratings  from  20  to  40  kw.  or  35  to 
67  kva.  Various  shaped  horns,  dies  and  other  equipment  are 
furnished  to  meet  special  demands. 

Examples  of  Spot- Welding  Work. — In  connection  with  the 
Thomson  machines,  the  welding  of  the  corners  of  a  sheet-steel 
box  is  shown  in  Fig.  231.  The  illustrations  in  Fig.  232  show 
how  the  lower  horn  is  raised  for  welding  side  seams  and 
dropped  for  welding  on  the  bottom  of  a  box. 

The  welding  of  small  hoe  blades  to  the  shanks   is  shown 


FIG.  238. — Welding  12-Gage  Iron  for  Guards. 

in  Fig.  233.  These  are  welded  at  the  rate  of  840  per  hour, 
the  shanks  being  bent  afterward.  Stove-pipe  dampers  are 
welded  as  shown  in  Fig.  234,  and  wire  lamp-shade  frames  are 
mash-welded  as  shown  in  Fig.  235.  Ordinary  wire  and  sheet- 
metal  oven  gratings  or  racks,  with  seven  cross-wires  welded 
to  the  end  pieces,  have  been  made  at  the  rate  of  100  racks 
per  hour,  or  1,400  mash-welds.  On  certain  kinds  of  wire  work, 
it  is  desirable  to  butt-weld,  and  for  this  purpose  the  attach- 
ment shown  in  Fig.  236  is  used.  In  general,  however,  where 
any  amount  of  this  kind  of  work  is  to  be  done,  it  is  better 


288 


ELECTRIC   WELDING 


to  employ  a  regular  butt-welding  machine  of  the  small  pedestal 
or  bench  type. 

The  spot-welding  of  galvanized  ventilating  pipe  is  shown 
in  Fig.  237,  and  in  Fig.  238  is  shown  the  welding  of  12  gage 
sheet  steel  machine  guards.  In  this  illustration  the  operator 
is  using  the  foot-treadle  which  leaves  his  hands  free  to 
manipulate  the  work.  In  Fig.  239  the  operator  is  welding 
gas-stove  parts  and  the  foot-treadle  is  thrown  back  out  of  the 


FIG.  239. — Welding  Stove  Parts,  Using  a  Swinging  Bracket  Support. 

way.  A  special  bracket  is  employed  to  hold  the  work.  The 
joints  of  this  bracket  are  ball-bearing,  making  it  very  easy 
to  swing  the  work  exactly  where  it  is  wanted  to  obtain  the 
spot-welds. 

POINTS  FOR  SPOT  WELDING 

The  form  of  spot-welding  points  shown  in  Fig.  240,  says 
A.  A.  Karcher,  has  been  developed  by  the  Challenge  Machinery 
Co.,  Grand  Rapids,  Mich.,  with  gratifying  results.  Fig.  241 
shows  a  typical  weld  and  indicates  the  neatness,  slight  dis- 


SPOT-WELDING  MACHINES  AND  WORK  289 


FIG.  240.— Form  of  Points  for  Spot  Welding. 


FIG.  241. — Spot  Weld  Showing  Slight  Discoloration  and  Freedom  from  Flash. 


290 


ELECTRIC  WELDING 


coloration  of  the  metal  and  entire  freedom  from  flash  either 
on  the  outside  or  between  the  parts.  In  one  view  the  dis- 
colorations  give  an  erroneous  impression  of  the  existence  of 
bosses  on  the  face  of  the  metal,  which  is  actually  flat  except 
for  the  depressions  at  the  points  of  the  welds. 

The  shape  of  the  points  would  lead  one  to  expect  that  the 
small  projections  would  require  a  lot  of  attention  to  keep 
them  in  shape.  Experience  shows,  however,  that  this  is  not 
the  case,  as  the  points  actually  lengthen  slightly  and  occasion- 
ally have  to  be  filed  down. 

Even  when  a  weld  is  made  close  to  the  edge  the  operation 
is  quicker  and  consumes  less  current.  A  little  practice  in 
determining  the  correct  amount  of  current  to  use  is  all  there 
is  to  learn  in  handling  these  points. 

SIZES  OF  DIE-POINTS  FOR  LIGHT  WORK 

The  data  on  the  size  of  die-points  in  Fig.  242  arc  given  on 
the  authority  of  Lucien  Haas,  and  may  be  considered  good 


Rounded 
Points 


FIG.  242. — Sizes  of  Die  Points  for  Light  Work. 

general  practice.     These  points  are  intended  for  welding  two 
pieces  of  the  same  gage  and  material. 

On  certain  kinds  of  heavy  spot-welding  work  circular  metal 
disks  are  placed  between  the  plates  in  order  to  localize  the 
current  and  to  provide  good  contact.  In  other  cases,  projec- 
tions are  made  in  one  or  both  of  the  plates.  These  latter, 
of  course,  necessitate  a  mechanical  or  press  operation,  previous 


SPOT-WELDING   MACHINES  AND  WORK 


291 


.Welding  Preware 


On  Completion  of  Heating  before 
Welding  Presiure  ia  Applied 


After  Completion  by  Arc  Welding, 
for  Calking  Purpoie 


TIG.  243.— The  Tit  or  Projection  Method  of  Welding. 


FIG.  244.— Winfield  Sliding  Horn  Spot- Welding  Machine. 


292 


ELECTRIC   WELDING 


FIG.  245. — Winfield  Heavy-Duty  Machine  with  Adjustable  Table. 


FlG.  246. — Winfield  Portable  Spot- Welding  Machine. 


SPOT-WELDING   MACHINES  AND   WORK 


293 


to  welding.  Heavy  plate  work  is  shown  in  Fig.  243.  At  the 
upper  left  are  shown  plates  as  commonly  arranged  for  welding. 
Next  to  this  is  a  plate  with  a  projection  under  the  upper  die- 


FIG.  247. — Winfield  Portable  Machine  with  Swivel  Head. 

point.  A  steel  plunger  is  used  in  the  lower  die  to  give  the 
needed  pressure  after  the  metal  is  heated.  This  saves  crushing 
or  distorting  the  soft  copper.  In  the  lower  right-hand  corner 


294 


ELECTRIC  WELDING 


FIG.  248. — Small  Winfield  Bench  Machine. 


FIG.  249. — Winfield  Machine  with   Suspended  Head   for  Welding 
Automobile  Bodies. 


SPOT-WELDING   MACHINES  AND  WORK 


293 


is  shown  a  ridge  or  tit  weld,  after  the  seam  has  been  arc- 
welded. 

The  Winfield  Machines. — The  machines  made  by  the  Win- 
field  Electric  Welding  Machine  Co.,  Warren,  Ohio,  comprise 
a  varied  line  for  every  conceivable  spot-welding  purpose.  In 
general,  Figs.  244  and  245  may  be  taken  as  typical  of  their 


FIG.  250. — Convenient  Setting  of  Machine  for  Sheet  Metal  Work. 


light  and  heavy  spot-welding  machines.  Fig.  246  shows  a 
very  convenient  form  of  portable  machine.  In  Fig.  247  is 
shown  a  much  heavier  portable  machine  with  swiveling  head, 
and  in  Fig.  248  is  a  small  bench  machine  that  is  exceedingly 
useful  for  light  work. 


296 


ELECTRIC  WELDING 


A  very  interesting  machine  is  shown  in  Fig.  249.  This 
has  the  entire  head  suspended  from  the  ceiling,  so  that  work, 
like  the  automobile  body  shown,  may  be  worked  under  it. 


FIG.  251. — Federal  Welding  Machine  with  Universal  Points. 

This  machine  is  in  use  in  the  plant  of  the  Herbert  Manu- 
facturing Co.,  Detroit. 

A  good  way  to  place  a  machine  for  some  work  is  shown 
in  Fig.   250.     This  is  employed  in  the   shop   of  the  Terrell 


SPOT-WELDING   MACHINES   AND   WORK 


297 


Equipment  Co.,  Grand  Rapids,  Mich.,  in  the  manufacture  of 
steel  lockers,  steel  furniture  and  the  like. 

Federal  Welding  Machines. — A  feature  of  the  spot-welding 
machines  made  by  the  Federal  Machine  and  Welder  Co.,  War- 
ren, Ohio,  are  the  "universal"  welding  points  used  on  most 
of  their  output.  The  principle  will  be  instantly  grasped  by 


FIG.  252. — A  Few  Positions  of  the  Universal  Points. 

referring  to  Fig.  251.    Some  of  the  different  positions  possible 
are  shown  in  Fig.  252. 

Another  feature  of  these  machines,  is  the  use  of  the  type 
of  water-cooled  points  shown  in  Fig.  253.  The  welding  point 
is  copper  and  it  is  attached  to  the  holder  in  such  a  way  that 
the  water  flows  within  half  an  inch  of  the  actual  welding 
contact. 


298 


ELECTRIC  WELDING 


In  general  form,  size  and  capacities,  the  Federal  line  does 
not  differ  materially  from  the  machines  already  shown. 


PIG.  253. — Federal  Water-Cooled  Points. 


FEDERAL  ROTATABLE  HEAD  TWO-SPOT  WELDING  MACHINE 

The  rotatable  head  two-spot,  air  operated  welding  machine, 
shown  in  Fig.  254,  a  60-in.  throat  depth  and  is  guaranteed 
to  weld  from  two  thicknesses  of  24-gage  up  to  two  thicknesses 


SPOT-WELDING   MACHINES  AND  WORK 


299 


of  8-gage  steel  stock.  Twelve  welds  per  minute  may  be  made 
in  the  latter  size. 

The  machine  is  built  with  a  4  kva.  welding  transformer 
in  the  upper  and  lower  rotating  heads.  Primaries  are  in 
parallel  while  the  secondaries  are  in  series,  so  that  two  spot 
welds  must  be  made  at  the  same  time. 

The  welding  electrodes  or  points  are  1J  in.  in  diameter, 
are  carried  in  water-cooled  holders,  and  are  so  arranged  that 


FIG.  254. — Federal  Rotatable  Head  Two-spot  Welding  Machine. 

welds  from  3  to  8  in.  apart  may  be  made.  The  ends  of  each 
set  of  welding  points  can  be  separated  a  maximum  of  5  in. 
The  heads  can  be  rotated  through  an  angle  of  90  deg.  to  permit 
welding  at  different  angles  on  the  stock  being  handled. 

Four  air  cylinders  are  used,  each  operating  an  independent 
point.  The  air  control  is  hand  operated  and  so  arranged  that 
an  initial  air  line  supply  pressure  of  80  Ib.  will  give  from 
300  to  700  Ib.  pressure  between  the  points  during  the  heating 
period.  A  second  step  on  the  air  control  makes  it  possible 


300 


ELECTRIC   WELDING 


to  apply  1,200  Ib.  pressure  between  the  points  for  the  final 
squeeze.  The  air  is  exhausted  into  the  reverse  side  of  the 
cylinders  to  withdraw  the  points.  The  regulating  transformer 
supplies  power  to  the  welding  transformer  in  eight  voltage 
steps. 

FEDERAL  AUTOMATIC  SPOT-WELDER  FOR  CHANNELS 

The  machine  shown  in  Fig.  255  was  made  for  spot-welding 
two  rolled  steel  channels  together  to  form  an  I-beam.     It  is 


FIG.  255. — Federal  Channel  Welding  Machine. 

capable  of  welding  two  spots  at  a  time  on  two  pieces  of 
material  J  in.  thick,  at  the  rate  of  60  welds  per  min.  The 
two  welding  transformers  are  for  220  volts  primary,  and  are 
air  cooled.  Four  copper  disks  are  used  for  welding  contacts. 
These  are  securely  bolted  to  bronze  shafts  to  insure  good  elec- 
trical connections.  The  secondaries  of  the  welding  trans- 
formers are  connected  to  the  brass  bearings  of  these  shafts,  com- 
pleting the  welding  circuit. 

The   welding  current  is  controlled   by  auto  transformers 


SPOT-WELDING  MACHINES  AND  WORK 


301 


in  the  primary  circuit  in  eight  equal  steps  from  65  per  cent 
to  full  line  voltage. 

The  welding  disks  can  be  adjusted  to  handle  from  4  to  16 
in.  channels.  Simultaneous  spot  welds  from  4  to  12  in.  apart 
may  be  made.  A  variable  speed  motor  is  used  to  control  the 
feeding  of  the  work  through  the  machine  at  from  25  to  60 
ft.  per  min. 

AUTOMATIC  PULLEY  WELDING  MACHINE 

The  machine  shown  in  Fig.  256  was  made  to  weld  the  ring 
section  of  pressed-metal  pulleys,  known  as  the  filler,  to  the 


FIG.  256. — Automatic  Electric  Pulley  Welder. 

rim  itself.  This  ring,  or  filler,  not  only  acts  as  a  stiffener 
for  the  rim,  but  is  the  part  to  which  the  outer  ends  of  the 
spokes  are  attached. 

In  welding,  one-half  of  a  pulley  rim  is  locked  by  means 
of  a  chain-clamping  device  to  a  rotating  carrier,  with  the  filler 
and  spokes  in  place  as  shown.  An  adjustable  mandrel  on  the 


302 


ELECTRIC  WELDING 


carrier  insures  the  proper  distance  between  the  center  of  the 
pulley  and  the  rim  face.  Duplicate  welding  sets  operate  on 
each  side  of  the  filler,  and  spot  weld  intermittently  as  the  work 
is  automatically  indexed  around. 

The  mechanical  part  of  the  machine  is  motor  driven,  and 
with  the  work  in  place,  the  machine  will  properly  space  and 
weld  around  the  filler  until  it  reaches  the  end,  when  it  auto- 
matically trips.  The  points  are  water  cooled  and  will  make 


FIG.  257. — Taylor  Cross-Current  Spot-Welding  Machine. 

about  60  welds  per  minute.  These  welding  points  can  be  set 
to  weld  within  2^  in.  of  the  center  of  the  mandrel  or  supporting 
shaft,  and  have  a  maximum  distance  adjustment  of  12  in. 
between  them.  The  automatic  indexing  or  feeding  device  is 
so  arranged  that  welds  from  £  to  3  in.  or  more  apart  may 
be  made.  Pulleys  from  12  in.  up  to  5  ft.  in  diameter  may 
be  handled,  all  the  necessary  adjustments  being  easily  and 
quickly  made  to  accommodate  the  various  sizes. 


SPOT-WELDING   MACHINES  AND   i^ORK 


$03 


This  machine  occupies  a  floor  space  of  about  30X66  in., 
weighs  about  3,500  Ib. 

The  Taylor  Welding  Machines. — While  the  machines  made 
by  the  Taylor  Welder  Co.,  Warren,  Ohio,  differ  radically  from 
others  on  the  market,  in  that  they  employ  double  electrodes 
and  cross  current,  the  forms  of  the  machines  are  about  the 
same  as  those  previously  shown.  An  automatic  belt-driven 
machine  of  the  lighter  type,  is  shown  in  Fig.  257.  It  may 


FIG.  258. — Taylor  Heavy-Duty  Machine. 

be  operated  by  the  foot-treadle  also  when  desired.  This 
machine  has  a  capacity  up  to  two  £-in.  plates.  The  horns  are 
water-cooled  and  the  adjustable  points  are  locked  in  with  a 
wrench  as  shown.  Fig.  258  shows  a  heavier  type  of  machine. 
This  has  a  capacity  of  two  j-in.  plates ;  overhang  is  36  in. ; 
distance  between  copper  bands  and  lower  horn,  6  in. ;  base, 
26x42  in.;  extreme  height,  72  in.;  greatest  opening  between 
welding  points,  3  in. ;  weight  about  2,400  Ib.  The  transformer 
is  35  kw.  and  there  is  a  ten-step  self-contained  regulator  for 


304 


ELECTRIC   WELDING 


controlling  the  current.    This  firm  makes  other  sizes  and  styles 
of  machines,  to  meet  all  the  demands  of  the  trade. 

The  general  principle  of  the  cross-current  welding  method 
employed  in  these  machines  is  illustrated  in  Fig.  259.  Two 
separate  currents  are  caused  to  flow  in  a  bias  direction  through 
the  material  to  be  welded.  A  high  heat  concentration  is  claimed 
for  this  method.  In  operation,  the  positives  of  two  separate 


CROS 


ENT 


SPO 


ING 


FIG.  259. — Diagram  of  the  Current  Action  in  a  Taylor  Machine. 

welding  currents  are  on  one  side  of  the  material  and  the 
negatives  on  the  other,  with  the  co-working  electrodes  of  each 
set  so  that  the  current  travels  diagonally  across.  An  advantage 
claimed  is  that  the  electrodes  on  each  side  of  the  material 
may  be  set  far  enough  apart  to  allow  of  the  insertion  of  some 
hard  material  which  will  take  the  pressure  instead  of  the 
softer  copper  welding  points.  These  hard  dies  may  be  operated 
independently  of  the  copper  ones  and  make  it  possible  to  weld 


SPOT-WELDING   MACHINES  AND  WORK 


305 


heavier  material  without  crushing  the  copper  die  points,  as 
these  need  to  be  pressed  together  only  enough  to  give  good 


FlG.  260. — Automatic  Hog-Ring  Machine. 


FIG.  261. — Partial  Rear  View  of  Hog-Ring  Machine. 

electrical  contact  with  the  work.     The  process  is  also  unique 
in  that  it  can  be  operated  with  a  multiphase  circuit  without 


306  ELECTRIC  WELDING 

unbalancing  the  lines,  whicli  is  not  the  case  with  any  spot- 
welding  machine  employing  a  single  current. 

Some  Special  Welding  Machines. — An  automatic  machine 
for  forming  and  mash-welding  11  gage  wire  hog  rings,  at  the 


FIG.  262. — Close-Up  of  Front  of  Hog-Ring  Machine. 

rate  of  60,000  per  day,  is  shown  in  Fig.  260.  This  machine 
takes  wire  from  two  reels  and  turns  out  the  complete  hog 
rings.  A  partial  rear  view  is  shown  in  Fig.  261.  A  close-up 
of  the  front  of  the  machine,  with  two  hog  rings  lying  on  the 
platen,  is  given  in  Fig.  262. 


SPOT-WELDING   MACHINES  AND  WORK 


307 


A  machine  in  use  in  the  punch  press  department  of  the 
General  Electric  Co.,  Schenectady,  N.  Y.,  is  shown  in  Fig.  263. 
This  machine  welds  small  spacers  to  the  iron  laminations  for 
motors  and  generators  for  ventilating  purposes,  and  hence  is 


FIG.  263. — General  Electric  Space-Block  Welding  Machine. 

called  a  " space-block  welder."  A  number  of  these  machines 
are  in  use  in  this  plant,  and  they  are  capable  of  welding  60 
spots  per  minute  when  working  continuously,  not  allowing  for 
time  to  shift  the  stock. 

A  combination  spot-  and  line-welding  machine,  used  in  the 


308 


ELECTRIC  WELDING 


General  Electric  Co.'s  shops,  is  shown  in  Fig.  264.  This  is 
employed  for  welding  oil  switch  boxes  up  to  -J  in.  thick.  As 
shown,  the  machine  is  fitted  with  a  fixture  for  holding  the 
boxes  while  line-welding  the  seams.  A  separate  fixture  is  put 


FIG.  264. — Combination    Spot-    and    Line-Welding    Machine,    Set    Up    for 
Line- Weld  ing  Can  Seams. 

on  for  spot-welding  work.     A  seam  6  in.  long  can  be  line- 
welded  on  this  machine. 

Another  combination  machine,  used  in  the  same  shops,  is 
shown  in  Fig.  265.  This  machine  carries  both  the  spot-  and 
the  line-welding  fixtures  at  the  same  time.  Fig.  266  shows 
the  machine  from  the  line-welding  side.  As  shown,  the 


SPOT-WELDING   MACHINES  AND   WORK 


309 


machines  are  ready  for  welding  straight  plates.  Machines  of 
this  kind  should  find  a  considerable  field  where  it  is  desired 
to  tack  seams  before  line  welding  them.  These  machines  have 


FIG.  265. — A  Combination  Machine  from  the  Spot- Weld  ing  Side. 

a  capacity  of  20  kva.,  and  will  weld  up  to  3/16  in-  thick,  and 
seams  18  in.  long. 

Line  welding  machines,  as  developed  in  the  Schenectady 
plant,  comprise  a  transformer  with  a  one  turn  secondary, 
through  which  a  heavy  current  is  delivered  at  low  voltage  to 
the  material  through  the  medium  of  a  stationary  jaw  and  roll- 


310 


ELECTRIC   WELDING 


ing  wheel.  Both  the  jaw  and  wheel  are  water-cooled  and 
pressure  is  applied  to  the  wheel  the  same  as  to  a  spot-welding 
tip.  A  small  revolving  switch  mechanically  geared  to  the 
driving  motor  and  welding  wheel  operates  a  set  of  contactors 


FIG.  266. — Machine  from  the  Line- Weld  ing  Side. 

or  solenoid  switches  to  throw  the  power  on  onco  a  second,  the 
power  being  on  f  of  a  second,  and  off  f  of  a  second.  The 
mechanism  is  synchronized  so  that  during  the  f  of  a  second 
the  power  is  on,  the  welding  wheel  is  rolling,  and  during  the 


SPOT- WELDING   MACHINES  AND  WORK  311 

remaining  f  of  a  second  the  wheel  is  stationary  under  pressure 
while  the  soft  metal  is  solidifying,  thus  completing  the  weld. 
Spot- Welding  Machines  for  Ship  Work.— During  the  World 
War,  welding  of  all  kinds  took  huge  steps  forward.  Spot- 
welding  developed  at  least  as  much  as  any  other  kind.  Writing 
in  the  General  Electrical  Review,  J.  M.  Weed  says: 

The  machines  to  be  described  are  two  portable  welders,  one  with  12-in. 
reach  and  the  other  with  27-in.  reach,  for  use  in  the  fabrication  of 
structural  ship  parts,  and  one  stationary  machine  with  6-ft.  reach  designed 
for  welding  two  spots  at  the  same  time  on  large  ship  plates. 

A  preliminary  survey  of  the  structural  work  in  shipbuilding  indicated 
that  about  80  per  cent  of  this  work  could  be  done  by  a  machine  of  12-in. 
reach,  and  that  a  27-in.  reach  would  include  the  other  20  per  cent.  Since 
both  the  weight  of  the  machine  and  the  kva.  required  for  its  operation 
are  about  33  per  cent  greater  for  the  27-in.  reach  than  for  the  12-in., 
it  seemed  advisable  to  develop  two  machines  rather  than  one  with  the 
longer  reach. 

These  machines  were  to  a  certain  obvious  extent  patterned  after  the 
riveting  machines,  which  they  were  intended  to  replace  as  will  be  seen 
from  Fig.  267.  They  are  necessarily  considerably  heavier  than  the  riveting 
machines,  but  like  these  they  are  provided  with  bales  for  crane  suspension, 
for  the  purpose  of  carrying  the  machines  around  the  assembled  work  or 
parts  to  be  welded. 

The  maximum  welding  current  available-  in  these  machines,  with  a  steel 
plate  enclosed  to  the  full  deptn  of  the  gap,  is  about  37,500  amperes,  with 
the  maximum  applied  voltage  of  534  volts  at  60  cycles.  Reduced  voltages, 
giving  smaller  currents,  are  obtained  in  six  equal  steps,  ranging  from 
534  down  to  267  volts,  from  the  taps  of  the  regulating  transformers 
furnished  with  the  machines. 

This  wide  range  of  voltage  and  current  was  provided  in  order  to  meet 
the  possible  requirements  for  a  considerable  range  in  thickness  of  work, 
and  for  experimental  purposes.  Tests  have  shown,  however,  that  the 
machines  will  operate  satisfactorily  on  work  of  thicknesses  over  the  range 
on  which  they  are  likely  to  be  used  when  connected  directly  on  a  440-volt, 
60-cycle  circuit,  with  no  regulating  transformers.  Two  plates  £-in.  thiek 
are  welded  together  in  spots  from  1  in.  to  1£  in.  in  diameter,  in  from 
12  to  15  seconds.  Thicker  plates  require  more  time  and  thinner  plates 
less  time. 

The  welding  current  under  these  conditions  is  about  31,000  amp.;  the 
primary  current  is  about  600  amp.  for  the  12-in.  machine  and  about  800 
amp.  for  the  27-in.  machine,  the  corresponding  kva.  at  440  volts,  being 
265  and  350  respectively. 

Since  the  reactance  of  the  welding  circuit  is  large  as  compared  with 
the  resistance,  the  voltage  necessary  for  a  given  current,  and  conse- 
quently the  kva.  necessary  for  the  operation  of  the  machine,  is 
almost  proportional  to  the  frequency.  Thus,  these  machines  operate  satis- 


312 


ELECTRIC  WELDING 


factorily  from  a  25-cycle  circuit  at  220  volts,  with  the  advantage  that 
where  the  power-factor  is  from  30  to  40  per  cent  at  60  cycles,  it  is  from 
60  to  75  per  cent  at  25  cycles,  and  the  kva.  required  at  25  cycles  is  about 
one-half  that  required  at  60  cycles. 

The  maximum  mechanical  pressure  on  the  work  for  which  those  machines 
are  designed  is  25,000  Ib.  This  is  obtained  from  an  8-in.  air  cylinder, 
with  an  air  pressure  of  100  Ib.  per  square  inch,  acting  through  a  lever 
arm  of  5  to  1  ratio.  Lower  pressures  on  the  work  are  obtained  with 


FlG.  267. — Portable  Spot-Welding  Machine  with  27-in.  Throat  Depth. 
Capable  of  Welding  Two  Plates  £  In.  Thick  in  Spots  1  In.  in  Diameter. 
Made  by  the  General  Electric  Co. 

correspondingly  reduced  air  pressures.  A  pressure-reducing  valve  is  pro- 
vided for  this  purpose,  and  also  a  pressure  gage  for  indicating  the  pressure 
on  the  machine  side  of  the  valve. 

The  pressure  required  to  do  satisfactory  welding  depends  upon  the 
thickness  of  the  plates.  It  is  necessary  that  the  areas  to  be  welded  should 
at  the  start  be  brought  into  more  intimate  contact  than  the  surrounding 
areas,  in  order  that  the  current  may  be  properly  localized,  and  the  heat 


SPOT- WELDING   MACHINES  AND  WORK  313 

generated  in  the  region  where  it  is  needed.  It  is  therefore  necessary,  on 
account  of  irregularities  in  the  plate  surface,  that  the  pressure  should  be 
great  enough  to  spring  the  cold  plate  sufficiently  to  overcome  the  irregulari- 
ties. The  pressure  which  will  do  this  with  heavy  plates  is  ample  for 
effecting  the  weld  after  the  welding  temperature  is  reached. 

It  should  be  explained  in  this  connection  that  the  rate  of  heating  at 
the  surfaces  to  be  welded  depends  largely  upon  the  contact  resistance, 
and  consequently  upon  the  condition  of  the  plates  and  the  pressure  used. 
If  the  plates  are  clean  and  bright,  and  the  pressure  high,  the  rate  of 
heating  with  a  given  amount  of  current  is  slow  and  the  welding  efficiency 
is  poor.  This  makes  it  difficult  to  weld  heavy  plates  if  they  are  clean, 
since,  as  stated  above,  it  is  necessary  to  use  large  pressure  with  heavy 
plates  to  insure  a  better  contact  of  the  areas  to  be  welded  than  that  of 
surrounding  areas.  It  is  much  easier  to  weld  plates  which  carry  the 
original  coat  of  mill  scale,  or  a  fairly  heavy  coating  of  rust  or  dirt, 
affording  a  considerable  resistance  which  is  not  sensitive  to  pressure.  If 
this  resistance  is  too  great,  the  necessary  current  will  not  flow,  of  course, 
but  if  the  scale  is  not  too  heavy  it  has  little  effect  upon  the  current, 
the  high  reactance  of  the  welding  circuit  giving  it  practically  a  constant 
current  characteristic  and  making  the  rate  of  heating  proportional  to  the 
resistance  within  certain  limits.  The  scale  melts  at  about  the  welding 
temperature  of  the  steel,  and  is  squeezed  out  by  the  high  pressures  used, 
permitting  the  clean  surfaces  of  the  steel  to  come  together  and  effect 
a  good  weld. 

A  gage  pressure  of  about  70  lb.,  giving  17,500  Ib.  pressure  upon  the 
work,  has  been  found  to  give  good  results  under  these  conditions  in  ^-in. 
plates. 

Both  the  mechanical  pressure  and  the  current  are  transmitted  to  the 
work  in  these  machines  through  heavy  copper  blocks  or  welding  electrodes. 
The  shape  of  the  tips  of  these  electrodes  is  that  of  a  very  flat  truncated 
cone. 

The  severity  of  the  conditions  to  which  the  tips  of  the  electrodes 
are  subjected  will  be  understood  when  it  is  considered  that  the  current 
density  in  the  electrode  material  at  this  point  is  approximately  60,000 
amp.  per  square  inch,  and  that  this  material  is  in  contact  with  the  steel 
plates  which  are  brought  to  the  welding  temperature,  under  pressures  of 
15,000  to  20,000  lb.  per  square  inch.  It  must  be  remembered,  also,  that 
copper,  which  is  the  best  material  available  for  this  purpose,  softens  at 
a  temperature  considerably  lower  than  the  welding  temperature  of  steel. 
The  difficulty  of  making  the  electrode  tips  stand  up  under  the  conditions 
to  which  they  are  subjected  has,  in  fact,  constituted  the  most  serious 
problem  which  has  been  met  in  the  development  of  these  machines. 

The  shape  of  these  electrodes  gives  them  every  possible  advantage  in 
freely  conducting  the  current  to  and  the  heat  away  from  the  electrode 
tips,  and  in  giving  them  the  mechanical  reinforcement  of  the  cooler  sur- 
rounding material.  However,  it  has  been  found  necessary  to  reduce,  as 
far  as  possible,  the  heat  generated  at  the  tips  of  the  electrodes  by  cleaning 
the  rust  and  mill  scale  from  the  surfaces  of  the  plates  beneath  the  elec- 


314.  ELECTRIC  WELDING 

trodes.  The  most  convenient  way  which  has  been  found  for  ooing  this 
is  by  means  of  a  sand  blast.  The  bodies  of  the  electrodes  are  also  internally 
water-cooled  by  a  stream  of  water  flowing  continually  through  them.  Still, 
after  all  of  these  things  have  been  done,  a  gradual  deformation  of  the  tip 
of  the  electrode  will  occur,  increasing  its  area  of  contact  with  the  work, 
and  thus  reducing  the  current  density  in  the  work  and  the  pressure  density 
below  the  values  needed  for  welding.  This  would  make  it  necessary  to 
change  electrodes  and  to  reshape  the  tips  very  frequently,  and  the  total 
life  of  the  electrodes  would  be  short  on  account  of  the  frequent  dress- 
ings. 

An  effort  has  been  made  to  overcome  this  difficulty  by  protecting  the 
tip  of  the  electrode  by  a  thin  copper  cap,  which  may  be  quickly  and 
cheaply  replaced.  As  many  as  160  welds  have  been  made  with  a  single 
copper  cap,  yJ6  in.  thick,  before  it  became  necessary  to  replace  it.  Un- 
fortunately this  does  not  entirely  prevent  the  deformation  of  the  electrode 
tip,  but  it  stands  up  much  better  than  it  does  without  the  cap. 

Another  method  which  has  been  tried  for  overcoming  this  trouble  is 
by  making  the  tip  portion  of  the  electrode  removable,  in  the  form  of  a 
disk  or  button,  held  in  place  by  a  clamp  engaging  in  a  neck  or  groove 
on  the  electrode  body.  While  this  protects  the  electrode  body  from 
deformation  and  wear,  the  tip  itself  does  not  stand  up  so  well  as  does 
the  combination  of  electrode  and  cap,  where  the  tip  of  the  electrode  is 
not  separated  from  the  body. 

Some  electrodes  have  been  prepared  which  combine  the  features  of 
the  removable  tip  and  cap.  These  give  the  advantage  of  a  permanent 
electrode  body,  and  the  removable  tip  with  the  protecting  cap  stand  up 
better  than  the  unprotected  tip. 

Some  interesting  features  were  introduced  in  the  design  of  the  trans- 
formers which  are  integral  parts  of  these  machines,  owing  to  the  necessity 
for  small  size  and  weight.  Internal  water  cooling  was  adopted  for  the 
windings,  which  makes  it  possible  to  use  current  densities  very  much 
higher  than  those  found  in  ordinary  power  transformers.  The  conductor 
for  the  primary  windings  is  §-in.X2'in'  copper  tubing,  which  was  obtained 
in  standard  lengths  and  annealed  before  winding  by  passing  it  through 
an  oven  which  is  used  for  annealing  sheathed  wire  during  the  process  of 
drawing.  No  difficulty  was  found  in  winding  this  tubing  directly  on  the 
insulated  core,  the  joints  between  lengths  being  made  by  brazing  with 
silver  solder.  The  entire  winding  consists  of  four  layers  of  thirteen  turns 
each  in  the  12-in.  machine  and  three  layers  of  thirteen  turns  each  in  the 
27-in.  machine. 

The  U-shaped  single-turn  secondaries  were  slipped  over  the  outside  of 
the  primary  windings  in  the  assembly  of  the  transformers.  These  were 
constructed  of  two  copper  plates  each  §  in.  thick  and  6|  in.  wide,  which 
wero  bent  to  the  proper  shape  in  the  blacksmith  shop,  and  assembled  one 
inside  the  other  with  a  ^-in.  space  between  them.  Narrow  strips  of  copper 
were  inserted  between  the  plates  along  the  edges,  and  the  plates  were 
brazed  to  these  strips,  thus  making  a  water-tight  chamber  or  passage  for 
the  circulation  of  the  cooling  water. 


SPOT-WELDING   MACHINES  AND  WORK  315 

At  31,000  amp.  the  current  density  in  these  secondaries  is  about  6,200 
amp.  per  square  inch,  the  corresponding  densities  in  the  primary  windings 
being  about  7,000  for  the  12-in.  and  9,000  for  the  27-in.  machine. 

In  case  these  machines  are  started  up  without  the  cooling  water  having 
been  turned  on,  the  temperature  rise  in  these  windings  will  be  rapid,  and 
in  order  to  avoid  the  danger  of  burning  the  insulation,  asbestos  and  mica 
have  been  used.  The  copper  tubing  was  taped  with  asbestos  tape,  and 
alternate  layers  of  sheet  asbestos  and  mica  pads  were  used  between  layers 
of  the  primary  winding,  and  between  primary  and  secondary  and  between 
primary  and  core.  Space  blocks  of  asbestos  lumber,  which  is  a  compound 
of  asbestos  and  Portland  cement,  were  used  at  the  ends  of  the  core 
and  at  the  ends  of  the  winding  layers.  The  complete  transformer,  after 
assembly,  was  impregnated  with  bakelite.  The  result  is  a  solid  mechanical 
unit  which  will  not  be  injured  by  temperatures  not  exceeding  150  deg.  C. 
Several  welds  could  be  made  without  turning  on  the  cooling  water  before 
this  temperature  would  be  reached. 

The  transformers  are  mounted  on  a  chamber  in  the  body  of  the  frame. 
The  long  end  of  the  U-shaped  secondary  runs  out  along  the  arm  of  the 
frame  and  bolts  directly  to  the  copper  base  upon  which  the  bottom  electrode 
is  mounted.  The  short  end  connects  to  the  base  of  the  top  electrode 
through  flexible  leads  of  laminated  copper,  to  permit  of  necessary  motion 
for  engaging  the  work. 

The  copper  bases  upon  which  the  electrodes  are  mounted  are  insulated 
from  the  frame  by  a  layer  of  mica,  the  bolts  which  hold  them  in  place 
being  also  insulated  by  mica. 

The  cooling  water  for  these  machines  is  divided  into  two  parallel 
paths,  one  being  through  the  primary  winding,  and  the  other  through  the 
secondary  and  the  electrodes  in  series.  Separate  valves  are  supplied  for 
independent  adjustment  of  the  flow  in  the  two  paths.  The  resistance  of 
ordinary  hydrant  water  is  sufficiently  great  as  to  cause  no  concern  regarding 
the  grounding  or  short-circuiting  of  the  windings  through  the  cooling  water, 
although  it  is  necessary  to  use  rubber  tubing  or  hose  for  leading  it  in 
and  out. 

Some  pieces  of  %y(2-in.  machine  steel  were  welded  in  seven  seconds 
with  a  current  of  33,000  amp.  They  were  afterward  clamped  in  a  vise 
and  hammered  into  U-shapes.  Small  pieces  were  sheared  from  the  seam 
where  two  £- in.  plates  had  been  welded  together  in  a  row  of  spots.  The 
pieces  of  the  plates  were  then  split  apart  with  a  cold  chisel  in  one  case, 
and  an  effort  was  made  to  do  so  in  the  other,  with  the  result  that  one 
piece  of  plate  broke  at  the  welds  before  the  welds  would  themselves  break. 
Such  tests  as  these  show  that  the  welds  are  at  least  as  strong  as  the 
material  on  which  the  welds  were  made.  Some  samples  of  the  £x2-in. 
stock  welded  together  in  the  same  manner  were  tested  by  bending  in  an 
edgewise  direction,  thus  subjecting  the  welds  to  a  shearing  torque.  The 
ultimate  strength  calculated  from  these  tests  was  in  the  neighborhood  of 
65,000  Ib.  per  square  inch.  These  tests  showed  also  a  very  tough  weld, 
the  deflection  being  almost  45  deg.  in  some  cases  before  the  final  rupture 
occurred.  The  maximum  load  occurred  with  a  deflection  of  from  3  to  5 


316 


ELECTRIC  WELDING 


deg.  with  a  very  gradual  reduction  in  the  load  from  this  time  till  the 
final  rupture. 

The  Duplex  Welding  Machine. — The  machine  shown  in  Fig.  268  was 
developed  for  the  application  of  electric  welding  as  a  substitute  for  riveting 
on  parts  of  the  ship  composed  of  large-sized  plates,  which  may  be  fabricated 
before  they  are  assembled  in  the  ship.  The  specification  to  which  it  was 
built  stated  that  it  should  have  a  6-ft.  reach  and  should  be  capable  of 
welding  together  two  plates  f  in.  thick  in  two  spots  at  the  same  time. 
A  machine  capable  of  doing  this  work,  with  a  6-ft.  gap,  is  necessarily 


FIG.  268. — Duplex  Spot-Welding  Machine.  Made  by  the  General  Electric 
Co.  6-ft.  Throat  Depth,  and  Capable  of  Welding  Together  Two  Steel 
Plates  |  In.  Thick,  in  Two  Spots  1£  In.  in  Diameter. 

so  heavy  as  to  preclude  even  semi-portability,  and  no  effort  was  made  in 
this  direction. 

With  the  welding  circuit  enclosing  a  6-ft.  gap,  and  carrying  the  very 
heavy  current  necessary  to  weld  f-in.  plates,  the  kva.  required  would  be 
very  large.  A  great  reduction  in  the  kva.  and  at  the  same  time  a  doubling 
of  the  work  done,  is  obtained  in  this  machine  by  the  use  of  two  trans- 
formers as  integral  parts  of  the  machine,  and  two  pairs  of  electrodes, 
thus  providing  for  the  welding  of  two  spots  at  the  same  time.  The 
transformers  are  mounted  in  the  frame  of  the  machine,  on  opposite  sides 
of  the  work,  and  as  near  to  the  welding  electrodes  as  possible,  so  as  to 


SPOT-WELDING   MACHINES  AND   WORK  317 

obtain  the  minimum  reactance  in  the  welding  circuit.  The  polarity  of 
the  electrodes  on  one  side  of  the  work  is  the  reverse  of  that  of  the  opposed 
electrodes,  thus  giving  a  series  arrangement  of  the  transformer  secondaries, 
the  current  from  each  transformer  flowing  through  both  of  the  spots  to 
be  welded. 

The  bottom  electrodes  are  stationary,  and  the  copper  bases  which  bear 
them  are  connected  rigidly  to  the  terminals  of  their  transformer,  while 
the  bases  which  carry  the  top  electrodes  are  connected  through  flexible 
leads  of  laminated  copper,  to  permit  of  the  motion  necessary  for  engaging 
the  work. 

Previous  tests  with  an  experimental  machine  had  shown  that,  to  suc- 
cessfully weld  two  spots  at  the  same  time  in  the  manner  adopted  here, 
it  is  necessary  that  the  pressures  shall  be  independently  applied.  Otherwise, 
due  to  inequalities  in  the  thickness  of  the  work,  or  in  the  wear  and  tear 
of  the  electrodes,  the  pressure  may  be  much  greater  on  one  of  the  spots 
than  on  the  other.  This  results  in  unequal  heating  in  the  two  spots.  The 
resistance  and  its  heating  effect  are  less  in  the  spot  with  the  greater 
pressure.  The  two  top  electrodes  in  this  machine  were  therefore  mounted 
on  separate  plungers,  operated  by  separate  pistons  through  independent 
levers. 

The  pressures  obtained  in  this  machine  with  an  air  pressure  of  100 
Ib.  per  square  inch,  are  30,000  Ib.  on  each  spot,  giving  a  total  pressure 
of  60,000  Ib.  which  must  be  exerted  by  the  frame  around  the  6-ft.  gap. 
The  necessary  strength  is  obtained  by  constructing  the  frame  of  two  steel 
plates,  each  2  in.  thick,  properly  spaced  and  rigidly  bolted  together. 

The  use  of  steel  in  this  case  is  easily  permissible  on  account  of  the 
restricted  area  of  the  welding  circuit  and  its  relative  position,  resulting 
in  small  tendency  for  magnetic  flux  to  enter  the  frame.  However,  the 
heads  carrying  the  electrodes,  being  in  close  proximity  to  the  welding 
circuit,  were  made  of  gun  metal. 

The  two  air  cylinders  are  mounted  on  a  cast-iron  bed-plate  in  the 
back  part  of  the  machine.  The  levers  connecting  the  pistons  to  the  electrode 
plungers,  which  are  7  ft.  in  length,  were  made  of  cast  steel,  in  order  to 
obtain  the  necessary  strength. 

The  maximum  welding  current  for  which  this  machine  was  designed  is 
50,000  amp.  This  current  is  obtained  with  500  volts  at  60  cycles  applied. 

The  distance  between  the  electrode  bodies  for  this  machine  is  fixed 
at  8  in.,  center  to  center,  but  the  distances  between  the  centers  of  the 
tips  may  be  easily  varied  from  6  in.  to  10  in.  by  shifting  the  tip  from 
the  center  of  the  body  toward  one  side  or  the  other. 

Provision  has  been  made  for  shifting  the  electrodes  on  their  bases  to 
positions  90  deg.  from  those  shown  in  the  picture,  thus  spacing  the  welds 
in  a  direction  along  the  axis  of  the  machine  instead  of  traverse  to  it. 

The  transformers  are  insulated  and  cooled  in  the  same  manner  as 
those  in  "the  semi-portable  machines.  The  windings  are  interlaced  in  order 
to  obtain  minimum  reactance,  the  primary  being  wound  in  two  layers  of 
14  turns  each,  one  inside  and  the  other  outside  of  the  single  turn  secondary. 

With  50,000  amp.  in  the  secondaries  of  these  transformers,  the  current 


318  ELECTRIC  WELDING 

in  tne  primary  is  1,800.  The  respective  current  densities  are  7,000  and 
9,000  amp.  per  square  inch.  The  kva.  entering  the  transformers  on  this 
basis,  the  two  primaries  being  in  series  on  500  volts,  is  450  for  each 
transformer. 

This   machine   also   has  been   provided   with   a  regulating  transformer 
for  applying  different  voltages  to  give  different  values  of  welding  current, 


FIG.  269.— General  Electric  Co.'s  Experimental  Spot-Welding  Machine. 
Current  Capacity  100,000  Amp.  Pressure  Capacity  36  Tons.  Has 
Welded  Three  Plates,  Each  1  In.  Thick. 

and  with  a  panel  carrying  the  necessary  selector  switches  and  contactor. 
The  maximum  voltage  provided  by  this  regulating  transformer  as  at 
present  constructed  is  440.  If  it  is  found  that  the  current  obtained  with 
this  voltage  is  not  sufficient  for  the  heaviest  work  which  it  is  desired  to 
do  with  this  machine,  the  maximum  voltage  may  be  changed  to  500. 

The  kva.  entering  the  transformers  of  440  volts  will  be  approximately 
350  each,  instead  of  450. 


SPOT-WELDING   MACHINES  AND  WORK  319 

In  order  that  this  machine  may  be  operated  from  any  ordinary  power 
circuit,  it  will  be  necessary  to  use  a  motor-generator  set  provided  with 
a  suitable  flywheel.  This  will  eliminate  the  bad  power-factor,  distribute 
the  load  equally  on  the  three  phases,  and  over  a  much  larger  interval  of 
time  for  each  weld,  thus  substituting  small  gradual  changes  in  power  for 
large  and  sudden  changes.  On  account  of  the  high  reactance  the  welding 
current  will  remain  practically  Constant  as  the  speed  of  the  motor-generator 
set  falls  away,  thus  favoring  the  utilization  of  the  flywheel.  The  total 
maximum  power  drawn  from  the  circuit  with  this  arrangement  would  be 
about  100  kilowatts. 


FIG.  270. — Portable  Machine  for  Mash- Welding  Square  or  Bound  Rods. 

A  Heavy  Experimental  Spot- Welding  Machine.  —  The 
machine  shown  in  Fig.  269  was  built  in  1918  by  the  General 
Electric  Co.,  in  order  to  investigate  the  possibilities  of  welding 
plates  from.  £  in.  up.  Three  plates  each  1  in.  thick  have  been 
welded  with  it.  The  machine  is  provided  with  a  2,000-kva. 
transformer,  having  a  capacity  of  100,000  amp.  at  20  volts. 
Hydraulic  pressures  up  to  36  tons  are  obtained  at  the  elec- 
trodes. Motor-generator  sets  of  500-  and  6,000-kva.  capacity 


320 


ELECTRIC  WELDING 


were  used.  From  the  nature  of  the  service,  it  was  apparent 
that  some  form  of  cooling  was  needed  at  the  contact  points. 
It  was  found,  however,  that  it  was  impossible  to  water-cool 
the  points  sufficiently  to  give  a  reasonable  life  to  the  electrodes 
if  they  were  kept  the  same  diameter  for  any  distance  from 
the  work.  In  consequence  heavy  masses  of  copper  were  placed 


FIG.  271. — Lorain  Machine  for  Spot- Welding  Electric  Rail  Bonds. 

as  close  to  the  points  of  contact  as  practicable.  By  doing  this 
it  was  possible  to  have  a  very  large  cooling  surface  at  the 
top  of  the  electrode  and  by  passing  water  through  this  part 
at  the  time  of  welding  and  between  welds,  the  joints  were  kept 
cool  enough  for  all  practical  purposes. 

A  portable  machine  for  making  mash-welds  for  splicing  or 
attaching  round  or  square  rods  cross-wise,  is  shown  in  Fig. 


SPOT-WELDING   MACHINES  AND  WORK  321 

270.  This  was  made  by  the  General  Electric  Co.,  for  ship- 
yard use. 

A  big  machine  for  spot-welding  electric  railway  bonds,  is 
shown  in  Fig.  271.  This  is  made  by  the  Lorain  Steel  Co., 
Johnstown,  Pa.  It  will  weld  two  plates  18  in.  long  and  3  in. 
wide  by  1  in.  thick,  each  plate  having  three  raised  "welding 
bosses. ' '  Pressure  as  high  as  35  tons  is  obtainable  and  current 
up. to  25,000  amp.  may  be  used. 

Spot- Welding  Data. — It  is  difficult  to  give  definite  costs  for 
spot  welding,  as  much  depends  on  the  operator.  A  careless 
or  inexperienced  operator  will  waste  more  current  than  a  good 
one,  and  various  conditions  of  the  metal  being  worked  on 
will  make  a  considerable  difference  at  times.  However,  the 
information  given  in  Table  XXIII,  which  is  furnished  by  the 
Winfield  Electric  Welding  Machine  Co.,  will  prove  of  value 
as  a  basis  for  calculations.  Tables  XXIV  and  XXV  will  also 
be  useful  to  use  in  connection  with  the  measurement  of  the 
thickness  of  sheets,  and  in  comparing  different  gages. 

TABLE  XXIII. — SPOT-WELDING  POWER  AND  COST  DATA 


Gauge 
Number 

Thickness  of 
Sheets  in 
Fractions  of 
an  Inch 

Thickness  of 
Sheets  in 
Decimals  of 
an  Inch 

K.  w. 

Required 

H.  P. 

Required 

Time  in 
Seconds 
to  Make 
a  Weld 

Cost  1000 
Welds  at  one 
Cent  per 
K.  W.  Hour 

30 

Vso 

.0125 

3.0 

4.2 

-.25 

.002 

28 

7«4 

.0156 

4.0 

5.6 

.3 

.003 

24 

7*0 

.0250 

5.0 

7.0 

.45 

.006 

20 

Vso 

.0375 

6.5 

9.2 

.6 

.011 

18 

Yso 

.0500 

8.0 

11.3 

.8 

.017 

16 

V* 

.0626 

9.5 

13.5 

1.0 

.026 

14 

Ye* 

.0781 

10.0 

14.2 

1.3 

.036 

12 

v« 

.1093 

12.0 

17.0 

1.6 

.052 

11 

% 

.1250 

13.0 

18.5 

1.7 

.061 

10 

Ye* 

.1406 

14.0 

19.9 

1.8 

.070 

9 

Ya2 

.  .1562 

15.0 

21.3 

1.9 

.079 

8 

"/64 

.1715 

16.0 

22.7 

2.0 

.088 

7 

Yl6 

.1875 

17.0 

24.1 

2.1 

.099 

6 

*/m 

.2031 

18.0 

25.6 

2.2 

.110 

5 

Y32 

.2187 

19.0 

27.0 

2.4 

.124 

4 

M/« 

.2343 

20.0 

28.4 

2.7 

.148 

3 

% 

.2500 

21.0 

29.8 

3.0 

.174 

As  the  cost  of  current  varies  in  different  places,  we  have  figured  the 
current  at  one  cent  per  K.  W.  hour  to  give  a  basis  for  calculating  the 
cost.  Multiply  the  cost  of  current  given  above  by  the  rate  per  K.  W.  hour 
you  pay  and  you  will  have  your  cost  per  1000  welds  for  current. 


322 


ELECTRIC  WELDING 


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SPOT-WELDING   MACHINES  AND  WORK 


323 


TABLE   XXV. — DECIMAL    EQUIVALENTS    OF    AN    INCH    FOR    MILLIMETERS, 
B.  &  S.  AND  BIRMINGHAM  WIRE  GAGES 


Decimal 
Inch 

Mill. 

Fra. 
In. 

B&S 

Birm 
Gge. 

Decimal 
Inch 

Mill. 

Fra. 
In. 

B&S 

Birn, 
Gge. 

Decimal 
Inch 

Mill. 

Fra. 
In. 

B&S 

Birm 
Gge. 

.00394 

.1 

.11443 

9 

.  296875 

It 

.00787 

.2 

.11811 

3.0 

.  29921 

7.6 

.010025 

30 

.12 

11 

.3 

1 

.011257 

29 

.  12204 

3.1 

.30314 

7.7 

.01181 

.3 

.125 

y* 

.30708 

7.8 

.012 

30 

.  12598 

3.2 

.31102 

7.9 

.012641 

28 

.  12849 

8 

.3125 

A 

.013 

29 

.  12992 

3.3 

.31496 

8.0 

.014 

28 

.  13385 

3.4 

.31889 

8.1 

.014195 

27 

.134 

10 

.  32283 

8.2 

.015625 

A 

.  13779 

3.5 

.  32495 

0 

.01575 

.4 

.  140625 

A 

.  32677 

8.3 

.01594 

26 

.14173 

3.6 

.328125 

ft 

.016 

27 

.  14428 

7 

.3307 

8.4 

.0179 

25 

.  14566 

3.7 

.33464 

8.5 

.018 

26 

.148 

9 

.  33858 

8.6 

.01968 

.5 

.  14960 

3.8 

.34 

0 

.02 

25 

.  15354 

3.9 

.34251 

8.7 

.0201 

24 

.  15625 

A 

.34375 

H 

.022 

24 

.  15748 

4.0 

.34645 

8.8 

.022571 

23 

.16141 

4.1 

.  35039 

8.9 

.02362 

.6 

.  16202 

6 

.  35433 

9.0 

.025 

23 

.165 

8 

.  35826 

9.1 

.025347 

22 

.16535 

4.2 

.359375 

11 

.02756 

.7 

.  16929 

4.3 

.  36220 

9.2 

.028 

22 

.171875 

ti 

.3648 

00 

.  02846 

21 

.  17322 

4.4 

.36614 

9.3 

.03125 

& 

.17716 

4.5 

.  37007 

9.4 

.03149 

.8 

.180 

7 

.37401 

9.5 

.03196 

20 

.1811 

4.6 

.375 

3A 

.032 

21 

.  18194 

5 

.  37795 

9.6 

.035 

20 

.  18503 

4.7 

.38 

00 

.  03543 

.9 

.1875 

A 

.38188 

9.7 

.03589 

19 

.  18897 

4.8 

.  38582 

9.8 

.  03937 

1.0 

.19291 

4.9 

.38976 

9.9 

.04030 

18 

.  19685 

5.0 

.  390625 

H 

.042 

19 

.  20078 

5.1 

.3937 

10.0 

.0433 

1.1 

.203 

6 

.  39763 

10.1 

.04525 

17 

.203125 

if 

.40157 

10.2 

.  46875 

A 

.20431 

4 

.40551 

10.3 

.04724 

1.2 

.  20472 

5.2 

.  40625 

M 

.049 

18 

.  20866 

5.3 

.40499 

10.4 

.05082 

16 

.21259 

5.4 

.4096 

000 

.05118 

1.3 

.21653 

5.5 

.41338 

10.5 

.05512 

1.4 

.21875 

A 

.41732 

10.6 

.  05706 

15 

.22 

5 

.42125 

10.7 

.058 

17 

.22047 

5.6 

.421875 

11 

.05905 

1.5 

.2244 

5.7 

.425 

000 

.0625 

f0 

.  22834 

5.8 

.42519 

10.8 

.  06299 

1.6 

.  22942 

3 

.42913 

10.9 

.06408 

14 

.23228 

5.9 

.43307 

11.0 

.065 

16 

.234375 

tt 

.437 

11.1 

.06692 

1.7 

.  23622 

6.0 

.4375 

A 

.07086 

1.8 

.238 

4 

.44094 

11.2 

.07196 

13 

.24015 

6.1 

.44488 

11.3 

.072 

15 

.  24409 

6.2 

.44881 

11.4 

.0748 

1.9 

.  24803 

6.3 

.  45275 

11.5 

.078125 

A 

.25 

M 

.453125 

«i 

.  07874 

2.0 

.25196 

6.4 

.454 

0000 

.080801 

12 

.2559 

6.5 

.45669 

11.6 

.  08267 

2.1 

.  25763 

2 

.46 

0000 

.083 

14 

.259 

3 

.46062 

11.7 

.08661 

2.2 

.  25984 

6.6 

.46456 

11.8 

.09055 

2.3 

.  26377 

6.7 

.4685 

11.9 

.09074 

11 

.  265625 

H 

.  46875 

M 

.  09375 

& 

.26771 

6.8 

.47244 

12.0 

.09448 

2.4 

.27165 

6.9 

.47637 

12.1 

.095 

13 

.  27559 

7.0 

.48031 

12.2 

.09842 

2.5 

.  27952 

7.1 

.48425 

12.3 

.10189 

10 

.28125 

A 

.  484375 

l-i 

• 

.  10236 

2.6 

.  28346 

7.2 

.48818 

12.4 

.10629 

2.7 

.284 

2 

.49212 

12.5 

.109 

12 

.2874 

7.3 

.  49606 

12.6 

.  109375 

A 

.2893 

1 

.49999 

12.7 

.11023 

2.8 

.29133 

7.4 

.  5 

Yi 

.11417 

2.9 

.  29527 

7.5 

.50393 

12.8 

< 

z 

a: 
o 


0 
z 

I 


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UJ  LU 

>  5 

Z  fc 


Lr.J 


CHAPTER  XIV 

WELDING  BOILER  TUBES  BY  THE  ELECTRIC 
RESISTANCE    PROCESS 

About  1912  the  resistance,  or  Thomson,  process  of  electric 
welding  was  first  tried  out  in  a  locomotive  shop  for  the  purpose 
of  replacing  the  oil-furnace  welding  equipment  in  safe-ending 
boiler  tubes  up  to  2^  in.  in  diameter,  says  P.  T.  Van  Bibber, 
in  the  American  Machinist.  At  the  present  time,  in  shops  in 
different  parts  of  the  country  where  electric  welding  machines 
have  been  installed,  one  will  find  many  enthusiastic  " boosters" 
for  this  process.  It  is  to  these  users  that  we  are  indebted  for 
the  information  contained  in  this  article  and  for  the  benefit 
of  those  who  are  unfamiliar  with  this  adaptation  of  resistance 
welding,  an  endeavor  has  been  made  to  cover  all  the  details 
possible. 

In  using  the  resistance  type  of  machine  for  welding  safe- 
ends  onto  locomotive-boiler  flues,  the  old  tube  and  the  new 
safe-end  are  gripped  securely  in  heavy  copper  jaws  with  the 
ends  to  be  joined  held  in  alignment.  As  these  ends  are 
pressed  together  a  large  volume  of  current  from  the  secondary 
winding  of  the  transformer  is  passed  through  them.  Since  the 
junction  of  the  abutting  ends  is  the  point  of  greatest  resistance 
to  the  electric  current,  the  greatest  heating  effect  is  there 
and,  usually,  on  a  2^-in.  tube  it  requires  only  about  15  sec. 
to  secure  a  perfect  running  or  welding  heat.  A  slight  push-up 
by  the  pressure  device  on  the  welding  machine  sticks  the  two 
parts  together  solidly  enough  so  that  the  tube  can  be  removed 
to  the  mandrel  of  a  rolling  machine,  exactly  as  is  done  when 
welding  by  the  oil-furnace  method,  and  the  weld  is  then  com- 
pleted in  a  few  seconds  by  rolling  down  the  joint. 

Since  it  is  always  necessary  to  scarf  the  ends  of  a  tube 
and  new  safe-end  before  welding  by  the  oil-furnace 
method,  the  first  question  that  the  practical  boiler-shop  man 

324 


WELDING  BOILER  TUBES 


325 


will  ask  is,  How  much  preparation  is  needed  for  electric  resist- 
ance welding?  The  first  step  in  any  method  is  to  clear  the 
tube  from  heavy  scale,  if  in  use  under  bad  water  conditions, 
by  rolling  in  a  large  tumbling  barrel.  After  this,  the  tubes 
are  cut  to  the  desired  length  to  remove  the  old  end  that  is 
to  be  replaced  by  the  new  section. 

In  some  shops  it  is  the  practice  to  never  allow  more  than 
one  or  two  welds  in  a  tube,  which  means  that  after  removing 
the  second  time,  the  tube  must  be  used  in  a  shorter  boiler  than 
before.  This  procedure  is  carried  out  until  the  tube  can  only 


FlG.  272.— Machine  for  Cutting  Off  Flues. 

be  used  for  small  switching  locomotives — if  it  lasts  that  long 
— after  which  it  is  scrapped.  By  this  method,  only  one  length 
of  tube  is  bought  new,  which  is  that  required  for  the  longest 
boilers. 

In  other  shops  the  writer  found  tubes  with  many  welds, 
showing  that  the  safe-ending  was  continued  in  order  to  main- 
tain the  same  length  each  time  until  the  tube  was  worn  out, 
when  it  was  replaced  by  a  new  one  of  the  required  length. 
This  latter  method  necessitates  buying  several  lengths  new 
but  in  localities  where  the  water  is  not  very  hard  on  tubes, 
it  prevents  a  tube  from  going  to  the  scrap  pile  as  long  as  there 


326 


ELECTRIC  WELDING 


is  any  good  in  it.    After  cutting  off  the  old  tubes,  as  shown 
in  Fig.  272,  which  represents  a  common  type  of  machine  for 
this  purpose,  the  tubes  are  next  scarfed,  or  cut  off  square, 
according  to  which  method  of  welding  is  to  be  employed. 
If  a  scarf  weld  is  to  be  used,  the  old  tube  is  generally 


////7////////////////y/w///^ 

^Y////////7///////////////. 

Old  Tube 

£ 

Hew  End     ' 

7/////////////////////////S 

Y////////////////////////// 

FIG.  273.— Ends  Prepared  for  Scarf- Weld. 


Fie.  274. — Bolt  Threading  Machine  Made  Into  a  Scarfing  Machine. 

beveled  on  the  outside  at  an  angle  of  from  45  to  60  deg., 
according  to  the  length  of  scarf  desired,  about  as  shown  in 
Fig.  273.  The  bevel  is  wholly  a  matter  of  personal  opinion 
for  just  as  good  welds  can  be  made  with  a  30-deg.  scarf  as 
when  one  of  60  deg.  is  used. 


WELDING   BOILER  TUBES 


327 


One  type  of  machine  used  for  scarfing  is  shown  in  Fig.  274. 
This  has  been  rigged  up  from  an  old  bolt-threading  machine. 
The  jaws  shown  at  the  left  are  for  gripping  the  old  tube  which 
is  then  fed  into  a  revolving  chuck  by  means  of  the  handwheel. 
This  chuck  contains  the  necessary  cutters  for  forming  the 
desired  bevel  on  the  outside  of  the  tube  end.  The  jaws  on 
the  right-hand  side  of  the  same  machine  grip  the  new  short 
ends  as  they  are  fed  onto  a  revolving  tapered  reamer,  which 
cuts  a  scarf  from  the  inside.  In  some  shops,  the  scarfing  is 
done  on  an  old  lathe  with  special  fixtures,  but  the  remodeled 
bolt-threading  machine  seems  to  offer  the  most  efficient  proposi- 
tion for,  with  this  type  of  machine,  it  is  possible  for  one  man 
to  scarf  over  60  tubes  and  ends  per  hour. 


Old  Tube 


End 


FIG.  275. — Ends  Prepared  for  a  Straight  Butt-Weld. 

If  a  straight  butt-weld  is  to  be  made  instead  of  scarfing 
the  ends  to  be  joined,  they  are  cut  off  squarely,  as  shown 
in  Fig.  275.  This  is  done  in  an  old  pipe-threading  machine, 
or  a  lathe,  so  that  when  placed  in  the  welding  machine,  the 
abutting  ends  will  be  in  contact  practically  all  the  way  around 
their  circumference.  Although  this  last  method  of  preparing 
work  may  sound  shorter  than  scarfing,  nevertheless,  from  actual 
observation  of  both  methods  in  different  shops,  the  former  is 
faster  by  nearly  two  to  one. 

After  preparing  the  ends  for  welding,  if  the  tubes  have 
not  already  been  tumbled  to  remove  all  scale,  which  usually 
leaves  the  outside  surface  quite  bright  and  clean,  it  is  necessary 
to  grind  the  surface  of  both  old  tube  and  new  ends  back  to 
a  distance  of  about  8  in.  in  order  to  secure  a  good  electrical 


328  ELECTRIC  WELDING 

contact  between  the  tube  metal  and  the  copper  jaws  of  the 
welding  machine. 

There  are  three  distinct  methods  of  welding  boiler  tubes, 
which  are  called  butt-,  scarf-  and  flash-welding,  the  latter 
producing  the  same  effect  as  a  scarfed  joint  when  completed. 
In  the  straight  butt-weld,  the  ends  to  be  joined  are  first  brought 
firmly  together  by  means  of  the  pressure  device  on  the  welding 
machine,  and  the  current  is  then  turned  on.  There  is  always 
some  point  around  the  circumference  of  the  tube  which  starts 
to  heat  first,  due  to  the  impossibility  of  making  the  two  ends 
to  abut  with  the  same  pressure  at  all  points  of  their  contacting 
surfaces.  However,  the  heat  will  gradually  become  uniform 
all  around  the  circumference  before  the  welding  temperature 
is  reached.  The  current  is  maintained  through  the  tubes  until 
the  joint  reaches  a  good  running  heat,  as  evidenced  by  a 
" greasy"  appearance  of  the  surface,  when  the  pressure  is 
applied  sufficiently  to  push  up  the  hot  metal  about  -J  in.  which 
partly  completes  the  weld.  The  jaws  are  then  released  and 
the  tube  is  immediately  thrust  onto  the  mandrel  of  the  rolling 
apparatus,  which  is  described  further  on,  and  the  bulge  at 
the  joint,  caused  by  the  pushing  up  of  the  hot  metal,  is  rolled 
down  until  the  joint  is  of  the  same  diameter  as  the  original 
tube. 

This  rolling-down  operation,  in  addition  to  reducing  this 
bulge  of  the  tube,  also  forces  a  complete  union  of  the  plastic 
metal  of  the  two  pieces,  thereby  completing  the  weld.  From 
this  it  may  be  seen  that  in  welding  boiler  tubes,  the  welding 
machine  is  only  used  for  a  heating  device  to  supplant  the  oil 
furnace,  requiring  only  sufficient  pressure  to  stick  the  ends 
together  to  hold  it  while  removing  work  to  the  rolling  machine 
where  the  welding  is  finished. 

In  the  scarf  weld,  the  beveled  end  of  the  old  tube  is  pushed 
into  the  chamfered  end  of  the  new  piece  and  the  current  then 
turned  on  the  same  as  in  making  the  butt-weld  just  described. 
Due  to  the  "feather"  edge  of  the  short  new  piece,  it  is  often 
necessary  to  apply  the  current  intermittently  until  the  joint 
is  well  heated  all  around  the  circumference;  otherwise  points 
of  the  sharp  edge,  which  come  in  contact  first  with  the  opposite 
member,  will  be  burned  off  before  the  heat  is  evenly  distributed 
around  the  tube.  Owing  to  the  expanding  effect  of  the  scarfed 


WELDING   BOILER  TUBES 


329 


ends,  it  is  not  necessary  to  apply  so  much  pressure  as  with 
the  butt-weld  when  the  metal  is  plastic  in  order  to  stick  the 
pieces  together  before  rolling  down. 

With  either  of  the  above  welds,  it  is  necessary  to  give  the 
old  tube  more  projection  beyond  the  copper  clamping  jaws 
than  is  given  the  new  short  piece.  This  is  because  the  wall 
thickness  of  the  old  tube  has  been  slightly  reduced  by  wearing 
away  in  service  and  if  the  two  parts  were  given  the  same 
projection,  the  end  of  old  tube  would  heat  much  more  rapidly 
than  that  of  the  new  piece  since  its  resistance  to  the  electric 
current  would  be  greater,  owing  to  the  reduced  sectional  area. 
It  is  always  necessary  for  the  heat  to  form  uniformly  in  each 


Old  Tube 


New  End 


FIG.  276. — Ends  Prepared  for  a  Flash- Weld. 

of  the  abutting  ends  or  one  will  burn  away  before  the  other 
reaches  the  plastic  stage. 

In  making  a  flash-weld,  not  so  much  preparation  is  required 
as  for  the  two  other  methods  just  described;  hence  it  is  a 
much  cheaper  job  and  yet,  from  all  tests  made  so  far,  it  is 
the  only  type  of  joint  which  is  always  100  per  cent  perfect 
when  considering  the  number  of  defective  welds  in  any  lot 
of  tubes.  The  old  tube  is  cut  off  the  right  length  in  a  machine, 
which  has  a  cutting  wheel  so  beveled  as  to  give  an  angle  of 
30  deg.  from  the  vertical  on  the  end  of  the  tube,  as  shown  in 
Fig.  276.  The  new  ends  are  bought  direct  from  the  tube 
manufacturers  with  both  ends  cut  square  and  the  surface 
cleaned  well  so  that  there  is  no  preparation  needed  on  the 
new  pieces.  After  cutting  off  the.  old  tube  it  is  only  necessary 
to  grind  it  on  the  outside  about  8  in.  back  from  the  end  to 
insure  good  electrical  contact.  The  old  tube  is  placed  in  the 


330  ELECTRIC  WELDING 

clamps  with  about  4  in.  of  projection  and  the  new  end  with 
about  3  in.  The  current  is  turned  on  first  and  the  pressure 
is  then  applied  very  slowly  and  steadily  to  bring  the  abutting 
ends  into  contact.  As  soon  as  they  meet,  a  small  arc  or  '  *  flash ' ' 
is  formed  which  commences  to  burn  away  the  points  of  metal 
coming  into  contact  first.  This  flashing  is  continued  until  the 
abutting  ends  are  arcing  all  the  way  around  the  circumference 
and  by  this  time  the  sharp  edge  of  the  old  tube,  although 
somewhat  burned  away  itself,  has  burned  its  way  into  the 
square-cut  end  of  the  new  piece.  A  sudden  application  of  more 
pressure  stops  the  flashing  and  the  joint  then  quickly  attains 
the  running  or  welding  heat  as  in  the  butt-  or  scarf-welding 
method.  The  ends  are  now  shoved  together  and  as  the  current 
is  turned  off,  the  end  of  the  old  tube  will  have  forced  itself 
into  the  end  of  the  new  piece  sufficiently  to  form  a  scarf-weld 
when  rolled  down  in  the  rolling  machine. 

Using  a  Flux. — From  statements  made  by  every  operator 
interviewed,  the  use  of  flux  does  not  help  the  welding  in  any 
way;  yet  it  is  used  in  each  shop  because  it  clears  up  the 
surface  of  the  metal  when  the  plastic  stage  is  reached  and 
enables  the  operator  to  judge  the  appearance  of  the  heat  more 
easily.  The  writer  is  confident  that  if  a  new  operator  were 
to  be  broken  in  on  a  welding  machine,  he  would  soon  be  able 
to  correctly  judge  the  right  welding  heat  of  the  metal  by  its 
appearance  without  any  flux,  as  there  are  many  pipe  shops 
using  electric-welding  machines  for  making  joints  in  long  coils, 
where  flux  was  never  heard  of.  Each  railroad  shop  uses  a 
slightly  different  kind  of  flux,  but  generally  this  material  is 
nothing  more  than  a  common  yellow  clay,  streaked  with  quartz 
formation,  which  has  been  pulverized  and  thoroughly  dried 
out  before  using. 

There  are  several  methods  and  machines  employed  in  the 
various  shops  for  rolling  down  and  completing  the  weld  after 
heating  the  joint  properly.  One  of  the  simplest  machines  in 
use  is  shown  in  Fig.  277.  It  consists  of  a  power-driven  mandrel 
slightly  smaller  than  the  internal  tube  diameter,  above  which 
is  a  power-driven  roller.  This  roller  is  held  a  short  distance 
above  the  mandrel  by  a  spring.  When  the  hot  tube  is  thrust 
onto  the  mandrel,  the  upper  roller  is  brought  firmly  down  onto 
the  outside  surface  of  the  joint  by  pressure  on  a  foot  treadle 


WELDING   BOILER  TUBES 


331 


located  under  the  table  on  which  the  device  is  mounted.  The 
pressure  is  maintained  until  the  joint  has  been  rolled  down 
to  outer  tube  size.  The  main  disadvantage  of  this  style  of 
apparatus  is  that  the  speeds  of  the  roller  and  the  mandrel  must 
be  in  the  correct  ratio  so  as  to  not  allow  any  slip  on  either 
inner  or  outer  surface  of  the  tube,  otherwise  the  tube  will  roll 
unevenly  and  when  finished  will  have  a  thicker  wall  on  one 
side  than  on  the  other.  However,  this  is  the  earliest  form  of 
rolling  machine  used  with  the  electric-welding  method  and 


FIG.  277. — Simplest  Form  of  Boiling  Machine. 

is  still  giving  fairly  satisfactory  service  in  two  well-known 
shops  today. 

Another  type,  which  is  more  elaborate  but  more  positive, 
is  a  three-roller  machine,  shown  in  Fig.  278.  The  mandrel 
here  is  stationary  and  the  three  idling  rollers,  being  mounted 
on  a  power-driven  head,  continually  revolve  around  it.  After 
inserting  the  tube,  which  is  also  held  stationary,  pressure  is 
applied  by  means  of  a  hand  lever  which  closes  the  three  rollers 
in  toward  the  center  of  the  mandrel  and  the  joint  is  rolled 
down  by  the  surface  pressure  of  the  three  rollers  revolving 
around  it.  In  order  to  still  further  insure  uniform  rolling, 
the  tube  is  turned  slightly  on  the  mandrel  three  or  four  times 


332 


ELECTRIC  WELDING 


during  the  rolling  operation  since  the  mandrel  is  slightly 
smaller  than  the  tube  and  if  the  latter  were  to  be  held  in  only 
one  position,  a  difference  in  wall  thickness  on  one  side  might 
result. 

Rolling  machines  of  the  types  just  described  are  sometimes 
located  in  direct  alignment  with  the  jaws  of  the  welding 
machine,  so  that  after  obtaining  the  proper  heat,  it  is  only 
necessary  to  release  the  jaws  and  shove  the  hot  tube  directly 


FIG.  278. — The  Three-Boiler,  or  Hartz  Type,  Machine). 

onto  the  mandrel.  If  the  three-roller  type  is  being  used,  the 
tube  is  held  stationary  by  locking  one  jaw  of  the  welding 
machine.  When  a  new  position  on  the  mandrel  is  desired  the 
jaws  are  released  and  the  tube  allowed  to  turn  slightly  with 
the  friction  of  the  revolving  rollers. 

Another  method  is  to  have  the  rolling  machine  in  back  of 
the  welding  machine  so  that  when  the  correct  heat  is  obtained, 
the  tube  is  lifted  out  of  the  jaws  by  the  operator's  assistant 


WELDING  BOILER  TUBES  333 

who  shoves  it  onto  the  rolling  mandrel,  leaving  the  operator 
free  to  get  the  next  tube  lined  up  in  the  machine  for  heating. 
In  this  last  method,  the  assistant  must  act  quickly  so  as  not 
to  allow  the  joint  to  cool  down  before  the  rolling,  as  he  cannot 
transfer  the  tube  from  the  welding  to  the  rolling  machine  as 
quickly  as  the  operator  could  shove  it  forward  onto  the  mandrel 
as  first  mentioned. 

As  to  speed  in  welding,  the  writer  observed  that  the  same 
production  could  be  obtained  in  different  shops  by  either 
method  of  locating  the  rolling  machine ;  hence  it  is  purely  a 
matter  of  space  available  around  the  welding  machine,  and 
local  opinion. 

A  third  way  of  handling  the  rolling  down  is  to  have  the 
rolling  machine  built  onto  the  welding  machine,  as  shown  in 
Fig.  279.  In  this  particular  apparatus,  the  mandrel  is  made 
long  enough  to  permit  welding  in  to  a  distance  of  10  ft.  from 
the  joint,  so  as  to  reclaim  old  short  tubes  by  making  a  new 
long  one  with  a  joint  in  the  middle.  This  reclaiming  of  tubes 
has  proved  to  be  perfectly  practical,  having  been  forced  in 
one  locomotive  shop  during  the  war  due  to  the  inability  to 
obtain  new  tube  stock.  The  mandrel  is  power  driven  as  well 
as  the  upper  roller,  while  the  two  lower  rollers  are  idlers. 
After  obtaining  the  welding  heat,  it  is  only  necessary  to  move 
the  tube  about  one  foot  to  bring  the  joint  onto  the  rollers. 
A  clutch  at  the  rear  end  is  then  thrown  in  to  revolve  the 
mandrel  and  upper  roller,  and  pressure  is  applied  through  the 
latter  by  means  of  an  air  cylinder  mounted  above  it.  While 
being  rolled  the  tube  is  allowed  to  revolve  freely  in  the  open 
jaws  of  the  welding  machine.  The  rear  end  of  the  tube  is 
supported  on  idling  rollers. 

After  the  rolling-down  process,  which  is  the  same  as  has 
always  been  used  with  the  oil-furnace  method  of  welding,  the 
tubes  are  subjected  to  the  annealing  and  end-swaging  processes. 
They  are  then  usually  tested  hydrostatically  for  possible  leaks 
and  stacked  away  ready  for  assembling  in  the  boiler.  The 
percentage  of  leaks  is  less  than  5  per  cent  in  any  shop,  and 
in  one  shop  they  are  so  sure  of  their  welding  that  the  tubes 
are  not  tested  until  completely  assembled  in  the  boiler  when 
the  latter  is  subjected  to  a  hydrostatic  test  as  a  complete  unit. 
This  particular  shop  uses  the  flash-weld  method  and  has  never 


334 


ELECTRIC  WELDING 


I 

I 
be 


WELDING  BOILER  TUBES  335 

had  a  defective  joint  since  the  welding  machine  was  installed 
over  four  years  ago. 

Merits  of  Electric  and  Oil  Heating. — When  asked  to  com- 
pare the  electric  welding  with  the  oil-furnace  method  on  boiler 
tubes  of  any  size,  one  of  the  oldest  users  of  the  former  replied 
that  there  was  "no  comparison."  Using  oil  it  was  never 
possible  to  average  over  30  or  40  welds  per  hour  on  tubes 
up  to  3  in.  with  one  furnace  and  one  gang.  This  meant  that 
the  tube  shop  was  always  behind  the  rest  of  the  repair  depart- 
ments and  working  overtime  a  great  deal  in  order  to  catch  up. 
Fuel  oil  will  vary  greatly  in  different  lots  as  well  as  under 
different  atmospheric  conditions,  so  the  oil  furnace  itself  is 
a  constant  source  of  aggravation  and  calls  for  continual  adjust- 
ing, which  means  an  interruption  in  production  while  the  fire 
is  regulated. 

As  to  production  with  an  electric-welding  machine,  the 
average  output  on  tubes  up  to  3  in.  in  diameter,  taken  from 
all  shops  using  this  process,  will  run  60  completed  welds  per 
hour,  requiring  one  operator  and  a  helper  at  the  machine  and 
a  third  man  to  prepare  the  work  for  welding.  In  the  days 
of  piecework,  in  some  of  the  shops,  records  show  that  the 
maximum  number  of  small  tubes  turned  out  in  any  shop, 
with  the  same  number  of  men,  was  125  per  hour  or  a  little 
better  than  one  tube  every  30  sec.  and  this  could  be  kept  up 
for  two  hours  at  a  time  without  greatly  tiring  the  men.  This 
speed  was  obtained  by  three  different  shops,  each  using  a 
different  style  and  arrangement  of  rolling-down  apparatus, 
which  shows  that  all  of  the  methods  outlined  previously  in  this 
article  are  equally  fast. 

On  welding  superheater  tubes  at  the  reduced  section,  where 
the  diameter  at  the  point  of  weld  is  about  4f  in.,  the  production 
will  run  about  10  to  20  welds  per  hour,  although  better  time 
has  been  made  on  piecework.  By  comparing  these  figures  with 
the  oil-furnace  welding  production,  even  under  the  best  of 
working  conditions,  nothing  further  need  be  said  as  to  the 
speed  of  the  electric  process. 

As  to  cost,  there  are  no  figures  available  later  than  1916, 
which  of  course  would  be  much  lower  than  at  the  present  day, 
but  by  comparing  costs  of  both  methods  at  that  time,  taking 
into  consideration  upkeep,  labor,  cost  of  heat  either  way  and 


336  ELECTRIC  WELDING 

cost  of  time  lost  by  making  adjustments  or  repairs  to  either 
apparatus,  the  electric  costs  per  1,000  tubes  welded,  is  about 
one-third  that  of  the  oil-furnace  method. 

The  only  wear  on  the  welding  machine  is  the  surface  of 
the  copper  dies  or  jaws  which  grip  the  pieces  and  this  is  so 
slight  as  to  only  require  smoothing  off  a  few  times  a  week. 
The  machine  docs  not  cost  anything  for  heating  energy  except 
when  the  weld  is  being  made  and  it  is  always  ready  for  action 
as  soon  as  the  operator  has  placed  the  work  in  the  jaws.  Hence 
there  is  no  delay  in  starting  up  the  fire  in  the  morning  or 
after  lunch  hour  nor  from  the  fire  balking  at  any  time  during 
the  welding.  The  replacements  on  welding  machines  in  all 
the  shops  visited  by  the  writer  could  be  easily  covered  by  $100 
during  the  last  six  years. 

In  recapitulating  the  three  methods  of  electric  welding  flues, 
it  is  safe  to  say  that  the  flash-weld,  which  produces  a  scarfed 
joint  when  finished,  takes  the  lead  for  simplicity  of  preparation, 
speed  of  actual  welding  and  reliability  as  to  percentage  of 
failures  in  any  lot  of  tubes. 

Next  to  this  comes  the  straight  scarf-weld,  which  requires 
machining  of  the  ends  before  welding  but  insures  a  good  joint 
after  welding  although  occasionally  a  small  leak  will  show 
up  on  the  first  hydrostatic  test.  As  stated  before,  the  per- 
centage of  leaks  is  very  low  with  this  type  of  weld  and 
practically  negligible  with  the  flash-weld. 

The  butt-weld,  which  was  originally  employed  in  all  the 
shops,  is  now  only  used  in  one  shop  in  the  whole  country,  prob- 
ably due  to  the  difficulty  in  making  a  perfect  weld  each  time 
as  compared  to  the  ease  of  making  a  scarf  weld.  However, 
this  one  shop  claims  very  high  efficiency  with  a  butt-weld, 
both  as  to  tensile  strength,  which  will  average  over  85  per 
cent  of  original  tube  section,  and  as  to  tightness  of  the  joint 
under  pressure. 

The  principal  objection  offered  by  most  shops  against  butt- 
welding  is  that  should  the  weld  prove  tight  under  pressure, 
but  still  be  a  weak  joint  mechanically,  it  might  break  apart 
in  service.  This  has  happened  in  a  few  cases,  allowing  the 
tube  to  drop  down  in  the  boiler  and  subjecting  the  engine 
crew  to  the  danger  of  scalding.  With  a  scarf-weld,  which 
generally  shows  a  tensile  strength  equal  to  that  of  the  original 


WELDING  BOILER  TUBES 


337 


tube,  due  to  the  area  of  the  weld,  should  the  tube  not  be 
welded  strongly  as  just  cited  and  a  break  should  occur  inside 
the  boiler,  the  scarf  would  prevent  the  tube  from  pulling  away 
from  its  end  and  only  a  slow  leak  could  result.  This  some- 
times actually  happens  with  oil-furnace  welded  tubes. 

The  Kind  of  Machine  to  Use. — As  there  are  different  styles 
and  sizes  of  welding  machines  being  used  at  the  present  time 
on  flue-welding,  the  writer  will  endeavor  to  specify  special 
characteristics  that  should  be  sought  when  selecting  a  machine 
for  this  class  of  work,  which  is  different  from  any  other  pipe- 
welding  job.  The  machine  should  be  constructed  to  be  as 
efficient  electrically  as  possible ;  that  is,  the  clamping  jaw  should 
be  as  close  to  the  transformer  as  is  practical  in  order  not  to 

Copper  Jaws 


Recess*, 
-"s. 

/  \ 
Join 

fl 

Recess,  1 

_.,  JrLJ 

A 

•  —  1 

i 

Contact 

A 

i 

A 
i 

^Contact 

OldTube'         Wew  Tube 
End  View  Top  View 

FIG.  280. — Eecessed  Copper  Clamping  Jaws. 

have  large  inductive  losses  caused  by  the  large  gap  due  to 
the  long  secondary  leads  widely  spaced.  The  fewer  the  joints 
between  the  secondary  loop  of  the  transformer  and  the  copper 
jaws  which  grip  the  tube,  the  less  chance  will  there  be  for 
resistance  losses  that  cut  down  the  heating  effect  gradually  as 
oxides  form  in  the  joints  or  by  dirt  collecting  from  allowing 
them  to  become  loose.  Although  the  jaws  should  be  long  to 
permit  thorough  water  cooling,  it  is  only  necessary  to  grip 
the  pipe  over  a  length  of  about  2  in.  This  length  is  bored 
out  to  exactly  fit  around  the  tube  as  shown  in  Fig.  280. 

The  pressure  device  does  not  need  to  be  as  heavy  as  would 
be  used  on  the  same  welding  machine  for  joining  ordinary  pipe 
or  solid  stock,  since  the  squeezing  together  of  the  plastic  metal 


338  ELECTRIC  WELDING 

is  really  done  in  the  rolling  machine.  For  fastest  operation  the 
clamping  jaws  should  be  operated  by  air  cylinders  so  that  only 
a  slight  movement  of  two  valves  is  necessary  to  lock  or  unlock 
the  tube  in  the  jaws. 

For  welding  up  to  3-in.  size  tubes,  a  machine  of  30-kw. 
rating  ought  to  be  large  enough  to  stand  constant  use.  Any 
form  of  toggle  lever  or  screw-wheel  pressure  device,  which 
permits  the  operator  to  stand  close  to  the  work  will  be  suitable, 
as  not  over  1,000  Ib.  effective  pressure  is  required  on  this  size 
of  work  to  stick  the  ends  together  sufficiently  hard  for  placing 
in  the  rolling  machine. 

To  handle  up  to  5f-in.  superheater  tubes,  a  machine  of 
about  75-kw.  rating  should  be  employed.  For  its  pressure 
device,  an  air  cylinder  or  hydraulic  apparatus  may  be  used 
to  best  advantage  so  as  to  secure  up  to  three  or  four  tons' 
maximum  effective  pressure. 

For  ordinary  butt-  or  scarf-welding,  a  hand-operated  oil 
jack  may  be  used,  although  trouble  has  been  experienced  in 
the  past  with  this  type  of  pressure  device  due  to  sticking  of 
the  valves  at  critical  times,  often  spoiling  a  weld. 

Flash- Welding. — For  flash-welding,  a  toggle  lever  or  hand- 
screw  wheel  on  small  machines  and  an  air  cylinder  or  hydraulic 
pressure  device  on  large  machines  must  be  used,  to  effect  a 
slow  steady  forward  movement  of  the  movable  jaw  in  order 
to  maintain  the  arc  of  the  flashing,  yet  to  have  available  a 
quick  reverse  to  break  the  parts  away  should  they  stick  too 
soon  from  too  rapid  movement  of  the  pressure  device.  In  small 
shops,  it  is  advisable  to  install  a  75-kw.  machine  to  handle 
all  sizes  of  tubes  up  to  the  largest  superheater.  If  the  shop 
is  large  enough  to  keep  a  small  machine  busy  all  the  time  on 
tubes  up  to  3  in.,  it  will  no  doubt  pay  to  install  in  addition, 
a  large  machine  just  to  handle  the  superheater  tubes  as  well 
as  any  overflow  lot  of  small  tubes.  While  the  large  machine 
will  handle  any  size,  it  is  not  so  rapid  in  operation  on  small 
tubes  as  the  smaller  one,  and  the  bulk  of  flue-welding  is  on 
small  tubes,  less  than  10  per  cent  of  the  total  being  represented 
by  the  larger  sizes  for  superheaters. 


WELDING  BOILER  TUBES 


339 


WELDING  IN  THE  TOPEKA  SHOPS  OF  THE  SANTA  FE  RAILROAD 

Supplementing  the  foregoing,  we  give  the  following  extract 
from  an  article  published  in  the  American  Machinist,  June 
8,  1916: 

In  order  to  give  the  gripping  jaws  of  the  welder  good, 
clean  contact  the  ends  of  the  pieces  are  ground  on  the  outside 
for  about  6  or  7  in.  back  from  the  ends,  the  operator  simply 


FIG.  281. — Close-Up  Showing  Inside  Mandrel. 

revolving  the  tube  end  against  the  grinding  wheel.  The  ground 
pieces  are  sorted  out  into  suitable  lengths  to  form  full-length 
flues  when  two  pieces  are  butted  together,  keeping  in  mind 
that  only  two  welds  are  allowed  to  a  flue. 

The  butt-welding  machine  itself  is  practically  as  received, 
but  the  inside  mandrel  and  outside  rolls,  together  with  the 
driving  mechanism,  were  added  in  the  shop  after  considerable 
experimenting.  Without  these  the  method  would  be  a  failure. 

A  close-up  view  of  the  machine,  from  the  back,  is  given 
in  Fig.  281.  This  shows  the  mandrel  A  that  works  inside  the 


340 


ELECTRIC  WELDING 


FIG.  282.— Flue  Parts  Beady  for   Welding. 


FiG.  283. — Flue  Eiids  Just  Beginning  to  Heat. 


WELDING   BOILER  TUBES 


341 


FIG.  284. — Almost  Hot  Enough  for  Welding. 


FIG.  285. — Rolling  Out  the  Upset  Metal. 


342  ELECTRIC   WELDING 

flue  as  the  outside  is  rolled  between  the  three  rolls  after  the 
parts  have  been  heated  and  butted  together.  The  action  of 
the  mandrel  and  rolls  is  to  take  out  the  upset  and  give  a  weld 
that  is  smooth  on  the  outside  and  with  very  little  extra  metal 
inside.  The  gripping  jaws  are  water-cooled,  and  the  operating 
air  cylinders  are  plainly  shown. 

Fig.  282  shows  two  parts  of  a  flue  in  place  in  the  jaws 
and  illustrates  how  it  is  slipped  over  the  mandrel.  It  will 
be  observed  that  the  mandrel  does  not  extend  far  enough 
beyond  the  rolls  to  interfere  with  the  welding  or  become  heated 
from  the  current  passing  between  the  jaws.  As  it  is  impossible 
always  to  have  the  two  parts  to  be  welded  of  the  same  thick- 
ness, the  setting  of  the  pieces  in  the  jaws  must  be  done  with 
judgment.  If  one  piece  is  thinner  than  the  other  and  they 
were  both  set  in  the  jaws  the  same  distance  out,  the  thin  one 
would  burn  before  the  thick  one  was  hot  enough  to  weld 
properly.  To  avoid  this,  a  thick  and  a  thin  piece  are  placed 
about  as  shown  at  A  and  B.  In  this  case  the  thick  one  is  at 
A  and  the  thin  one  at  B.  As  the  thick  one  is  in  closer  to  the 
jaw,  it  will  heat  faster.  The  thin  one,  being  set  out  farther, 
gives  practically  the  same  amount  of  metal  for  the  current  to 
heat.  The  result  is  an  even  heating  and  a  perfect  weld. 

Fig.  283  shows  two  pieces  the  reverse  of  the  ones  just  shown. 
As  the  work  gradually  heats,  it  looks  as  in  Fig.  284.  At  the 
proper  heat,  the  operator  butts  the  work  together  to  form  the 
weld,  which  leaves  a  considerable  amount  of  upset.  He  then 
shoves  the  tube  along  over  the  mandrel  until  the  weld  is  be- 
tween the  rolls,  when  he  throws  in  the  clutch  and  brings  down 
the  upper  roll.  The  work  spins  between  the  rolls,  as  shown 
in  Fig.  285  and  the  result  looks  almost  like  a  new  tube. 


CHAPTER   XV 

ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL  AND 
STELLITE  IN  TOOL  MANUFACTURE 

The  cost  of  solid  high-speed  cutting  tools  is  high.  At  the 
same  time  their  remarkable  cutting  qualities  make  them  a 
necessity  in  up-to-date  shop  practice.  The  electric  process  of 
butt-welding  has  made  it  possible  to  obtain  all  the  advantages 
of  a  solid  high-speed  cutting  tool  and  yet  at  a  cost  that  is 
not  a  great  deal  higher  than  the  ordinary  tool-steel  product. 
Stellite,  -which  has  recently  become  more  widely  known,  has 
been  rather  limited  in  its  use  owing  to  the  fact  that  it  cannot 
be  machined,  and  it  has  been  thought  .by  many  that  it  could 
not  be  successfully  joined  to  any  other  metal  for  holding  it. 
This  has  limited  its  use  to  special  forms  of  toolholders,  which 
are  often  very  clumsy  in  getting  into  difficult  corners  on 
special  shapes.  The  electric  process  of  butt-welding  has  made 
it  possible  to  join  Stellite  bits  of  any  common  size  and  shape 
to  a  shank  of  ordinary  steel,  giving  all  the  advantages  of  a 
solid  cutting  tool  and  yet  employing  only  a  small  amount  of 
the  Stellite  metal  just  where  it  is  needed  for  cutting. 

The  Thomson  welding  process  consists  of  passing  a  large 
volume  of  electric  current  at  a  low  pressure  through  the  joint 
made  by  butting  two  pieces  of  metal  together.  The  electrical 
resistance  of  the  metals  at  the  contacting  surface  is  so  great 
that  they  soon  become  heated  to  a  welding  temperature.  Pres- 
sure is  then  applied  mechanically  and  -the  current  turned  off, 
thereby  producing  a  weld.  The  metal  is  in  full  view  of  the 
operator  at  all  times  instead  of  being  hidden  by  the  coal  of 
a  forge  or  by  flame  in  an  oil  furnace.  No  smoked  glasses  or 
goggles  are  required  any  more  than  would  be  if  welding  by 
the  forge  method.  Due  to  the  way  the  metal  is  forced  together 
there  is  no  oxidation  such  as  there  would  be  in  an  open  fire 
and  therefore  no  welding  compound  is  ordinarily  required. 

343 


344  ELECTRIC  WELDING 

It  is  this  feature  alone  which  makes  it  possible  to  weld  high- 
speed steel  and  Stellite,  the  former  being  very  difficult  to  weld 
by  the  forge  method  and  the  latter  practically  impossible. 
"With  this  process  of  electric  welding  the  heat  is  first  developed 
in  the  interior  of  the  metal.  Consequently,  it  is  welded  there 
as  perfectly  as  at  the  surface.  When  welding  with  other 
methods,  however,  the  outer  surface  is  heated  first  and  very 
often  the  interior  part  does  not  reach  welding  heat,  the  result 
being  an  imperfect  weld.  There  is  no  blistering  or  burning 
of  the  stock  when  welding  electrically,  whereas  it  certainly 
requires  a  very  expert  welder  indeed  to  secure  the  proper  heat 
on  high-speed  steel  in  a  forge  fire  without  burning  at  some 
point.  The  process  is  the  most  economical  known,  due  to  the 
fact  that  no  energy  in  the  form  of  heat  is  being  wasted  in 
heating  more  of  the  material  than  is  required  to  make  a  weld 
and  as  soon  as  it  has  been  completed  the  current  is  turned 
off  so  that  the  machine  then  is  not  using  up  any  energy  what- 
ever. The  operator  has  complete  control  of  the  current  at  all 
times  so  that  he  can  obtain  any  color  desired  on  the  metals, 
where  are  always  visible,  and  waste  by  accidental  burning  of 
metal  is  reduced  to  a  minimum. 

The  only  preparation  of  stock  necessary  for  welding  by  this 
process  is  that  when  very  rusty  or  greasy  it  should  be  thor- 
oughly cleaned,  as  the  presence  of  either  rust  or  heavy  grease 
affords  poor  contact  with  the  copper  clamping  jaws,  retarding 
the  flow  of  electricity  and  seriously  reducing  the  heating  effect. 

It  is  often  asked  if  the  electric  current  has  any  effect  on 
the  welded  metal.  This  question  arises  from  the  fear  that  there 
may  be  some  mysterious  condition  connected  with  electricity 
that  will  change  the  characteristics  of  the  metal,  particularly 
of  high-speed  steel  or  Stellite.  The  answer  is,  of  course,  in 
the  negative,  as  the  only  effect  of  the  electric  current  is  to 
heat  the  metals  being  welded. 

The  rapidity  of  work  will  depend  largely  on  the  operator, 
the  size  and  shape  of  the  pieces  to  be  welded  and  the  size  of 
machine  being  used,  as  there  is  a  wide  range  in  welding  time 
between  heavy  pieces  requiring  careful  alignment  in  the  clamp- 
ing jaws  and  light  pieces  which  can  be  rapidly  and  easily 
handled. 

Welding  High-Speed  to  Low-Carbon  Steel. — In  tool  welding 


ELECTRIC   WELDING  OF  HIGH-SPEED  STEEL 


345 


there  are  various  kinds  of  welds  to  be  made,  which  require 
different  designs  of  holding  jaws  and  often  two  distinct  types 
of  welding  machine. 

Three  butt-welding  machines  shown  in  Figs.  286,  287,  and 
288  are  especially  suitable  for  welding  drills,  reamers  or  other 


FIG.  286. — Thomson  10-A6  Butt -Welding  Machine. 

tools  that  can  be  made  up  of  a  combination  of  high-speed  and 
low-carbon  steel.  The  machine  shown  in  Fig.  286,  known  as 
the  10-A6  machine,  will  weld  iron  or  steel  rods  from  J  to  J  in. 
in  diameter,  or  an  equivalent  cross-section  in  squares,  rectangles 
or  flats.  An  operator  can  make  from  50  to  200  welds  per  hour, 
"'•.cording  to  the  size  and  nature  of  the  work  being  handled. 


346  ELECTRIC  WELDING 

The  clamps  are  of  the  horizontal  operating  type,  adjustable 
for  different  sizes  of  stock  as  well  as  for  horizontal  alignment 
of  the  work.  A  close-up  view  of  the  left-hand  clamping 
mechanism  is  shown  in  Fig.  287.  The  jaw  blocks  are  water 
cooled  and  have  a  maximum  movement  of  1J  in.  by  means 
of  the  hand-operated  clamping  levers.  There  is  also  a  possible 
f-in.  adjustment  of  both  front  and  rear  jaw  blocks.  Stops 
are  provided  for  backing  up  the  work.  There  are  four  copper 
jaws  to  a  set,  two  being  used  on  each  clamp.  These  jaws  are 


FIG.  287. — Closeup  View  of  Left-Hand  Clamp. 

2yz  in.  square  by  17/1C  in.  thick.  The  pressure  device  for 
forcing  the  heated  ends  of  the  work  together  is  a  hand-lever- 
operated  toggle  movement,  which  enables  the  operator  to  "feel" 
his  work.  This  toggle  device  gives  a  movement  of  1  in.  to 
the  right-hand  jaw.  The  maximum  space  possible  between 
the  jaws  is  3J  in.  There  is  an  automatic  current  cutoff  mounted 
on  the  machine.  The  standard  windings  are  for  220,  440  and 
550  volt,  60-cycle  alternating  current.  The  current  variation 
for  different  sized  stock  is  effected  through  a  five-point  switch 


ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL 


347 


mounted  on  the  machine.  Standard  ratings  are  15  kw.,  or 
25.  k.v.a.,  with  60  per  cent,  power  factor.  This  size  of  machine 
covers  a  floor  space  43X57  in.,  is  65  in.  high  and  weighs  about 
1100  pounds. 

The  machine  shown  in  Fig.  288,  or  the  No.  6  machine,  is 
for  heavier  work,  its  capacity  being  from  £  to  1  in.  in  diameter 
on  iron  or  steel  rods,  or  the  equivalent  in  other  shapes.  Its 
production  is  from  50  to  125  welds  per  hour.  The  maximum 
jaw  opening  is  3  in. ;  the  four  jaws  are  of  hard-drawn  copper, 
2JX2f  in.  and  1£  in.  thick;  toggle-lever  movement  1^  in.; 


FIG.  288. — No.  6  Butt-Welding  Machine. 

maximum  space  between  jaws,  4  in.;  current  standards  are 
the  same  as  for  the  previous  machine.  There  are  10  points  of 
current  variation  for  different  sized  stock,  effected  through 
double-control  switches  mounted  on  the  machine.  Standard 
ratings  are  30  kw.  or  45  kva.,  with  60  per  cent,  power  factor. 
The  jaws  are  air  cooled,  but  the  copper  slides  to  which  the 
jaws  are  bolted,  as  well  as  the  secondary  copper  casting  of 
the  transformer,  are  water  cooled.  It  occupies  a  floor  space 
22X44  in.  and  the  height  to  center  line  of  the  jaws  is  37^  in. 
The  weight  is  3100  Ib.  Its  operation  is  practically  the  same 
as  the  first  machine  described. 

Another  machine  of  very  similar  characteristics  is  shown 


348 


ELECTRIC   WELDING 


in  Fig.  289.  This  is  known  as  the  Special  5-D  machine  and 
is  intended  for  the  use  of  makers  of  small  taps  and  twist  drills 
up  to  f  in.  in  diameter.  It  has  very  accurate  adjustments  on 


FIG.  289.— Special  5-D  Machine. 

the  clamps  and  special  jaws  with  steel  inserts  to  prevent  wear. 
To  use  these,  however,  requires  that  the  pieces  to  be  welded 
must  be  finished  to  uniform  size  so  as  to  accurately  fit  the  jaws 
in  order  to  conduct  the  current  properly. 


FIG.  290. — Stellite-Tipped  Roughing  Drills. 

The  machines  shown  in  Figs.  286  and  288  are  not  only 
good  for  welding  the  steels  mentioned,  but  also  for  Stellite 
work,  samples  of  which  are  shown  in  Fig.- 290,  since  the  com- 


ELECTRIC   WELDING  OF  HIGH-SPEED  STEEL 


349 


monly  used  bits  of  this  metal  are  within  their  range.  The 
hand-lever  toggle  action  is  quicker  and  is  better  suited  to  this 
work  than  the  hydraulic-pressure  device  used  on  some  of  the 
larger  machines. 

In  welding  twist  drill  or  reamer  blanks,  such  as  shown  in 
Fig.  291,  not  over  }  in.  in  diameter,  it  has  been  found  practical 


FIG.  291.— Twist-Drill  Blanks  Just  Welded. 

to  use  a  pair  of  jaws  on  each  side  that  will  handle  all  work 
from  the  smallest  up  to  the  J-in.  size.  These  jaws  are  made 
as  shown  in  Fig.  292.  The  two  rear,  or  movable,  jaws  on  each 
side  of  the  machine  are  flat  faced,  while  the  front,  or  stationary, 
jaws,  have  a  V-groove  cut  in  them  just  deep  enough  to  give 
clearance  for  the  smallest  size  of  stock  to  be  handled  in  contact 


Round  Stock 
being  welded 


MOVABLE: 
DIE 


STATIOtMRY 
DIE 


Section  Through  Dies  and  Work 

FIG.  292. — Copper  Jaws  for  Various  Sizes. 

with  the  face  of  the  opposite  jaw.  The  work  is  held  in  the 
jaws  with  a  three-point  contact,  which  has  been  found  to  be 
sufficient  for  stock  of  this  size,  although  it  is  not  to  be  recom- 
mended for  larger  work,  since  not  enough  current  could  be 
carried  into  the  pieces  without  applying  pressure  sufficient  to 
squeeze  the  work  into  the  surface  of  the  copper  jaws.  This 
would  soon  spoil  all  accuracy  of  alignment  of  the  V-grooves. 


350 


ELECTRIC   WELDING 


In  this  connection  it  may  be  well  to  mention  that  a  welding 
machine  is  not  a  micrometer  and  the  welding  of  finished  pieces 
is  not  recommended  in  commercial  production,  although  such 
welding  is  done  right  along  for  special  jobs.  By  "special 
jobs"  is  meant  the  putting  on  of  an  extension  to  a  drill,  tap 
or  small  reamer  and  the  like. 

In  welding  high-speed  to  low-carbon  steel  the  low-carbon 
steel  sliould  project  approximately  twice  as  far  out  from  the 
jaws  as  the  high-speed  steel  does  in  order  to  equalize  as  much 
as  possible  the  heating  of  the  two  pieces. 

Where  a  tool  is  to  be  made  with  a  head  larger  than  the 
shank,  as  shown  at  A,  Fig.  293,  holding  copper  jaws  should 


HIGH- 
SPEED 

STEEL 


I    WELD 


J 


LOW-CARBON  STEEL 


(A) 


LOW  CARBON 
STEEL 


(a)  JAWS  OFWELDER,GROOVED   /^, 
FOR  ROUND  STOCK  (  D  j 


End   View 
FIG.  293. — Copper  Jaws  for  Holding  Large  Heads  and  Small  Shanks. 


be  made  as  shown  at  D.  In  work  of  this  kind  the  dimension 
B  should  always  be  about  one-half  of  the  diameter  of  C.  The 
same  rule  holds  good  with  this  type  of  tool  blank  when  placing 
it  in  the  jaws  as  with  steel  of  the  same  relative  size ;  that  is, 
the  low-carbon  steel  should  project  about  twice  as  far  from 
the  jaws  as  the  high-speed  steel  since  the  high-speed  steel  has 
the  higher  resistance  and  lias  a  tendency  to  become  plastic 
sooner.  To  still  further  reduce  its  tendency  to  heat  up  quickly, 
the  resistance  should  be  reduced  as  much  as  possible  by  having 
the  jaws  as  good  a  fit  for  the  high-speed  piece  as  it  is  possible 
to  make  them.  Where  different  sizes  are  to  be  welded  it  is 
advisable  to  have  special  holding  jaws  for  each  separate  size 
of  high-speed  steel  head,  although  the  low-carbon  steel  pieces 
may  be  held  in  V-grooved  jaws  made  up  to  hold  several  sizes. 


ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL          351 


352 


ELECTRIC   WELDING 


This  is  the  practice  of  some  of  the  largest  makers  of  reamers 
and  large  drills. 

The  actual  use  of  the  machines  shown  for  the  work  outlined 
is  simplicity  itself.  The  work  is  placed  in  the  respective  jaws 
and  securely  locked  in  place  by  pulling  forward  the  two  levers 
shown  projecting  upward  on  each  machine.  In  addition  to 
the  grip  of  the  jaws  the  work  is  kept  from  any  possible  slip 
by  means  of  stops  against  which  the  outer  ends  of  the  work 
are  butted.  With  the  work  solidly  in  place  the  operator  pulls 


FIG.  295. — Close-up  of  Machine  with  Work  iu  Jaws. 

on  the  pressure  lever  at  the  right  of  the  machine  until  the 
ends  of  the  work  are  in  firm  contact.  He  then  turns  on  the 
current  by  means  of  a  push  button  conveniently  located  in  the 
pressure  lever,  and  when  the  proper  heat  is  reached,  which 
is  judged  by  the  color,  the  push  button  is  released.  This  shuts 
off  the  current  and  the  operator  then  applies  full  pressure  and 
the  weld  is  made. 

The  maximum  capacity  of  the  largest  of  the  three  machines 
described  is  1  in.  round  or  its  equivalent  in  other  shapes.  For 
larger  work  a  machine  similar  to  the  one  shown  in  Fig.  294 


ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL          353 

is  used.  This  is  known  as  a  No.  9  butt-welding  machine,  and 
its  capacity  is  from  £  to  1J  in.;  the  output  is  from  50  to  100 
welds  per  hour ;  the  maximum  jaw  opening  is  1 J  in. ;  the  four 
hard-drawn  copper  jaws  are  3  in.  high,  3J  in.  wide  and  1£  in. 
thick;  the  pressure  device  is  a  5-ton  hand-operated  hydraulic 
oil  jack ;  maximum  movement  with  jack,  2  in. ;  maximum  move- 
ment with  one  stroke  of  jack,  ^  in. ;  maximum  opening  between 
jaws,  4  in. ;  standard  windings  the  same  as  for  the  previous 
machines;  standard  ratings,  40  kw.  or  55  kva.,  with  60  per 


FIG.  296. — Steps  in  the  Making  of  a  Large  Reamer. 

cent,  power  factor ;  width  of  machine,  27  in. ;  length,  60  in. ; 
height,  46  in. ;  weight,  3900  pounds. 

A  closeup  of  this  machine,  with  a  large  reamer  blank  in 
the  jaws,  is  shown  in  Fig.  295,  and  progressive  steps  in  the 
making  of  the  reamer  are  shown  in  Fig.  296.  The  high-speed 
steel  piece  is  3  in.  long  by  If  in.  diameter,  and  the  machine- 
steel  piece  is  6  in.  long. 

Two  other  machines  (10-B  and  40- A2  models)  of  this  type 
suitable  for  heavy  tool  welding  may  be  mentioned.  They  are 
made  with  a  capacity  of  from  £  to  1J  and  from  1  to  2  in. 


354 


ELECTRIC  WELDING 


The  first  of  these  has  a  hand-operated  pressure  device  capable 
of  exerting  a  pressure  of  12  tons  and  it  weighs  7800  Ib.  The 
second  has  a  pressure  device  which  receives  its  initial  pressure 


FIG.  297.— A  Welded  and  a  Finished  Lathe  Tool. 

from  an  external  accumulator,  which  gives  an  effective  pres- 
sure of  23  tons;  it  weighs  8000  Ib.  and  is  64X105X48  in.  high. 
The  Welding  of  Other  Than  Round  Tools.— The  welding 


.WELD 


r- 

\HIGH-SPEED 
\     STEEL 


LOW-CARBON  STEEL 


FlG.  298. — How  the  Parts  Are  Arranged  for  Welding. 

of  tools  similar  to  the  ones  shown  in  Fig.  297,  intended  for 
lathe  or  planing-machine  tools,  may  be  done  in  any  of  the 
foregoing  machines.  The  cutting  parts  may  be  of  either  Stellite 


End  View  (a)D/£  BLOCKS  or  WELDER 

FIG.  299. — How  the  Parts  Are  Clamped  in  the  Jaws. 

or  high-speed  steel.  This  kind  of  welding  is  usually  employed 
by  manufacturing  concerns  in  their  own  toolrooms  in  order  to 
use  up  odd  bits  of  high-priced  steel  or  Stellite.  The  pieces  arc 


ELECTRIC   WELDING  OF   HIGH-SPEED  STEEL 


355 


prepared  about  as  shown  in  Fig.  298.    Jaws  for  holding  work 
of  this  kind  are  outlined  in  Fig.  299. 

Another  way  to  make  tools  for  lathe  or  planing-machine 
work  is  outlined  in  Fig.  300.  This  method  may  often  be 
employed  when  the  one  just  given  could  not.  As  can  be  seen, 


HIGHSPEED 
STEEL 


WELD- 


LOW  CARBON  STEEL 


FIG.  300. — Method  of  Preparing  for  an  Insert  Weld. 

in  order  to  properly  support  the  high-speed  steel  piece,  the 
low-carbon  steel  shank  is  milled  away  to  form  a  recess  for 
the  reception  of  the  high-speed  steel  bit.  The  welding  can 
be  done  on  any  of  the  machines  shown  provided  the  parts  are 
not  of  too  great  cross-section.  The  method  of  recessing  the 
copper  clamping  jaws  is  clearly  shown  in  Fig.  301. 


j 

Co) 

iws  recessed 
to  hold  pieces 

a 

a 

a 

1& 

r 

<-\       ,-> 

Jtt-:        ICAK 

?ED       '  ST 

T             SH, 

j  

>BON- 
r.EL 
W/t 

a 

Top  View  of  Work  Meld  Vertically 


BIT 


Ph 

he 

i 

yon 
sss 

Pieces  resting  on 
bottom  of  recess 

Front  View  of  Rear  Jaws  and  Work 
FIG.  301. — Jaws  Used  for  Holding  Work  in  Insert  Welding. 

The  perfect  success  of  a  welded  high-speed  tool  depends 
not  only  on  the  correct  welding  but  also  upon  the  correct 
treatment  after  the  welding  itself  has  been  accomplished.  It 
is  easily  seen  that  if  a  piece  of  high-speed  steel  is  welded  to 
a  piece  of  ordinary  carbon  steel  and  the  joint  allowed  to  cool 


356 


ELECTRIC  WELDING 


fairly  quickly  in  the  air  strains  will  be  set  up  at  the  joint 
for  the  reason  that  the  high-speed  steel  in  cooling  so  quickly, 
both  metals  become  hardened  more  or  less  but  to  a  different 
degree.  Hence  if  the  weld  is  subjected  to  any  great  strain 
under  these  conditions  it  will  break  either  at  the  joint  or  close 
by ,  due  to  the  strain.  It  is  therefore  very  evident  that 
immediately  after  welding  a  piece  of  high-speed  steel  to  carbon 
steel  the  work  should  be  immediately  put  into  some  sort  of 
furnace  to  be  annealed.  The  amount  of  time  that  the  tools 
should  be  left  in  the  furnace  for  thoroughly  heating  through 
and  the  amount  of  time  required  to  allow  the  pieces  to  cool 
down  to  room  temperature  depend  entirely  upon  the  size  and 

Sfa  tionaryja  ws,  only 


recesseq 

/ 
*•                    "A 

_______      _  _  — 

1 

-i 

1 

HIGH-  . 
SPEED 
BIT 

CARBON  f 
STEEL  "' 
SHANK 

Top  View  of  WorK  Held  Horizontally 

Piece  resting  on  bottom  ofrec&ss 


V 

T 

End  View  of  WorK 
in  Right-Hand  Jaws 

FIG.  302. — Jaws  Used  for  Stellite  Butt  Welding. 

character  of  tool  being  made.  However,  the  annealing  of  any 
piece  of  any  size  requires  that' the  work  be  left  in  the  furnace 
heated  to  at  least  a  dull  cherry  red  for  a  few  hours  and  allowed 
to  cool  very  slowly  in  the  furnace. 

If  a  welded  tool  is  not  properly  annealed  before  machining 
much  difficulty  is  often  experienced  from  hard  spots  being 
encountered  in  the  machining  of  the  pieces,  which  of  course 
is  more  or  less  disastrous  to  the  cutting  edges  of  the  tools  being 
used  in  the  machining  process. 

The  best  method  of  hardening  high-speed  steel  tools  after 
the  welding  and  machining  depends  also  greatly  upon  the  shape 
and  size. 

Welding    Stellite,— Although    the   welding   of   the   various 


ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL 


357 


grades  of  Stellite  is  not  difficult  there  is  a  certain  knack  in  the 
welding  and  also  in  the  clamping  of  the  stock  which  must  be 
fully  acquired  to  produce  satisfactory  results. 

The  welding  should  be  done  in  a  horizontal  butt-welding 
machine  with  a  quick-acting  hand-lever  pressure  device.  In 
butt-welding  round  drill  stock  or  rectangular  tool  stock  the 
pieces  should  be  held  as  shown  in  Fig.  302.  It  will  be  noticed 
that  the  projection  of  the  Stellite  beyond  the  copper  jaws 
is  very  short  indeed  while  the  projection  of  the  carbon-steel 


J 

aws  re<. 
hold  pn 

•essec/ 
>ces. 

\ 

to 

j        , 

HIGH---' 
SPEED 
BIT 

CARBON- 
STEEL 
SHANK 

Top  View  of  Work  held  Vertically 


SHANK 

,,r 

V- 

r 

Pieces  resi 
on  bottot 
recess 

mg 
n  of 

Front  View  of  Rear  Jaws  and  Work 
FIG.  303. — Jaws  Used  for  Stellite  Insert  Welding. 

piece  is  comparatively  long.  This  is  because  Stellite  has  a 
very  high  resistance  compared  with  the  carbon  steel.  Since 
in  this  work  the  heating  effect  varies  directly  with  the  resist- 
ance of  two  metals  the  heating  in  the  Stellite  should  be  retarded 
as  much  as  possible  by  surrounding  it  almost  completely  with 
the  copper  jaws.  The  correct  amount  of  projection  of  the 
carbon  steel  will  have  to  be  determined  by  experiment  in  each 
case  after  observing  with  each  setting  of  two  pieces  which  has 
the  tendency  to  heat  the  fastest. 

In  welding  in  cutting  bits  of  Stellite  by  the  insert-weld 
method  the  pieces  should  be  held  as  shown  in  Fig.  303. 


358 


ELECTRIC  WELDING 


It  will  be  seen  from  this  cut  that  the  copper  jaws  holding 
the  small  bit  nearly  surround  it  and  at  the  same  time  back 
up  the  piece  to  take  the  pressure  of  the  squeezing  up  of  the 


FIG.  304. — Vertical   Type  of  Welding  Machine. 

stock.  The  opposite  jaws  holding  the  carbon-steel  shank  do 
not  have  to  grip  very  much  of  the  metal  but  they  serve  to 
back  it  up  to  receive  the  force  of  the  pressure. 

In  the  welding  itself  the  current  is  applied  intermittently, 


ELECTRIC  WELDING  OF  HIGH-SPEED  STEEL 


359 


as  the  Stellite  usually  has  a  tendency  to  heat  very  rapidly, 
until  the  carbon  steel  is  fast  approaching  the  plastic  state. 
The  current  is  then  held  on  steadily  and  the  instant  the  Stellite 
metal  "runs,"  the  pressure  lever  is  given  a  quick  jerk  as  thje 
current  is  turned  off.  It  will  be  found  that  with  a  good  weld 
there  is  scarcely  any  push  up  of  the  stock  and  very  little  of  the 


FIG.  305.— Making  a  "Mash"  Insert  Weld  in  a  20-AV  Machine. 

metal  flows  out  at  the  joint,  requiring  little  grinding,  if  any, 
to  finish  the  tool. 

Unlike  high-speed  steel  Stellite  requires  no  further  heat 
treatment  or  attention  of  any  kind  if  it  is  welded  correctly. 
When  it  is  taken  out  of  the  welding  machine  the  tool  is  ready 
for  use  at  once  after  grinding  off  the  resulting  burr. 


360 


ELECTRIC  WELDING 


Where  large  numbers  of  tools  of  the  lathe  and  planing- 
machine  types  are  to  be  made,  such  as  shown  in  Fig.  300, 
the  highest  production  can  be  obtained  by  using  a  Vertical 


FIG.  306. — Large  40-AV  Vertical  Machine. 

type  of  welding  machine  built  on  the  lines  of  the  one  shown 
in  Fig.  304. 

This  machine  (10-AV  model)  has  a  capacity  of  two  pieces 
with  contact  areas  between  0.40  and  0.30  sq.  in.  for  pieces  with 
a  total  thickness  of  f  to  1J  in.  The  production  is  35  to  85 
tools  per  hour,  depending  on  the  size;  the  upper  and  lower 


ELECTRIC   WELDING  OF  HIGH-SPEED  STEEL          361 

jaws  are  of  hard-drawn  copper  1|X2J  in.  and  If  in.  thick; 
the  jaw  blocks  are  water  cooled;  the  machine  has  a  current 
variation  through  a  five-point "  switch  for  different  sizes  of 
stock;  standard  windings  are  for  alternating  current  220  440 
and  550  volt,  60  cycles;  standard  ratings,  15  kw.  or  25  kva. 
with  power  factor  of  60  per  cent. ;  the  pressure  device  is  hand 
operated,  giving  a  movement  of  2f  in. ;  maximum  space  between 
jaws,  3|  in.;  floor  space  occupied,  21 X  53  in.;  height,  75  in.: 
weight,  1200  pounds. 

A  larger  machine  (20-AV  model)  of  the  same  type  in  opera- 
tion is  shown  in  Fig.  305.  This  machine  gives  a  maximum  area 
of  contact  ranging  from  1|  to  1  sq.  in.  on  pieces  with  a  total 
thickness  from  1  up  to  2  in. ;  production  is  from  50  to  75  welds 
per  hour ;  there  is  a  throat  clearance  of  10  in. ;  the  copper 
jaws  are  2X3  in.  and  1|  in.  thick;  pressure  is  by  hand-toggle 


FIG.  307. — Jaws  and  Work  Arranged  for  a  "Mash"  Weld. 

lever  and  spring  cushion;  current  control,  as  in  the  other 
machines,  is  by  push  button  in  the  lever  operating  through  a 
magnetic  wall  switch;  the  jaw  blocks  are  water  cooled; 
standard  ratings  are  30  kw.  or  50  kva'.  with  60  per  cent,  power 
factor;  weight,  2200  pounds. 

Another  still  larger  machine  (40-AV  model)  is  shown  in 
Fig.  306.  Except  for  its  size  it  is  but  little  different  from 
the  two  just  described,  the  main  difference  being  the  hydraulic- 
pressure  device,  which  gives  an  effective  pressure  of  5  tons. 
This  machine  has  a  maximum  contact  area  of  3  sq.  in.  and 
will  weld  pieces  from  1-J.to  3  in.  total  thickness;  production, 
15  to  50  welds;  throat  depth,  6J  in.;  jaws,  2X4XH  in.  thick; 
maximum  movement  of  upper  jaw  block,  2  in. ;  movement 
with  one  stroke  of  lever,  f  in. ;  space  possible  between  jaws, 
3  in. ;  standard  ratings,  60  kw.  or  86  kva.  with  70  per  cent. 


362 


ELECTRIC  WELDING 


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ELECTRIC  WELDING   OF  HIGH-SPEED  STEEL 


363 


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364  ELECTRIC  WELDING 

power  factor;  size,  34X60  in.   by  79  in.  high;  weight,  3600 
pounds. 

For  welding  tools  on  these  machines  the  relative  thickness 
of  the  two  parts  should  be  about  that  shown  in  Fig.  307.  Under 
ordinary  conditions  the  dimension  A  should  be  about  one-third 
of  B  in  order  to  have  the  point  of  the  weld  nearest  the  jaw 
in  contact  with  the  high-speed  steel,  so  that  the  heating  effect 


FIG.  308. — Pieces   Grooved   to   Make  Better   Welds  with   Less   Current. 

will  be  lessened  and  its  fusion  point  retarded  until  the  low- 
carbon  steel  has  a  chance  to  heat  up  properly. 

In  order  to  obtain  the  best  results  tools  wider  than  1  in. 
and  with  a  recess  longer  than  1J  in.  should  be  grooved  as 
shown  in  Fig.  308.  This  reduces  the  section  in  actual  contact, 
thereby  requiring  less  current,  is  easier  and  quicker  to  heat 
and  assures  a  better  weld  over  the  entire  area  of  contact. 

In  order  to  assist  those  who  have  tool  or  other  butt-welding 
to  do  some  useful  data  are  given  in  Table  XXVI. 

In  Table  XXVII  is  given  the  proper  size  of  copper  wire  to 
use  to  connect  up  the  various  machines  mentioned  for  tool 
welding. 


CHAPTER   XVI 
ELECTRIC   SEAM   WELDING 

Seam  or  line  welding  is  the  process  of  joining  two  over- 
lapping edges  of  sheet  metal  for  their  entire  length  without 
the  application  of  any  solder  or  spelter  along  the  joint.  In 
the  Thomson  process  of  lap-seam  welding,  the  heat  is  produced 
by  passing  a  large  volume  of  electric  current  through  the 
edges  to  be  welded  by  means  of  a  copper  roller  on  one  side 
of  the  joint  and  a  copper  track  or  horn  underneath.  In  any 
electrical  path,  wherever  high  resistance  is  interposed,  heating 
will  result,  and  the  higher  the  resistance  to  the  current,  the 
greater  will  be  the  heating  effect.  In  the  electric  lap  seam 
welding  machines,  the  copper  roller  and  horn  are  good  con- 
ductors and  the  joint  between  the  edges  of  the  metal  to  be 
welded  is  the  point  of  highest  resistance.  On  this  account 
it  is  evident  that  the  greatest  heating  effect  will  be  at  that 
point.  As  the  roller  passes  over  the  joint,  heating  the  stock 
to  a  plastic  state  beneath  it,  pressure  is  applied  by  springs 
on  the  roller  which  forces  the  two  edges  together  as  fast  as 
they  are  heated.  Since  20  B.  &  S.  gage  or  lighter  metal  heats 
very  rapidly,  the  pressure  and  heating  can  be  effected  at  the 
same  instant  of  contact  by  the  roller,  and  it  is  possible  to 
weld  as  fast  as  6  in.  per  second. 

The  only  preparation  necessary  for  seam  welding  is  that 
the  stock  must  be  absolutely  clean,  that  is,  free  from  any  traces 
of  rust,  scale,  grease,  or  dirt,  if  a  tight,  well-appearing  joint 
is  desired.  If  it  is  not  necessary  for  the  joint  to  be  tight, 
it  will  not  be  necessary  to  have  the  stock  so  clean,  although 
heavy  scale  or  rust  will  obstruct  the  passage  of  current,  so  that 
little  or  no  heating  effect  can  be  secured  under  these  conditions. 

In  welding  sheet  brass  of  22  to  30  B.  &  S.  gage,  to  secure 
a  perfect  joint  the  metal  should  be  carefully  pickled  and  washed 
to  remove  all  traces  of  grease  and  tarnish  which  tend  to  prevent 

365 


366  ELECTRIC   WELDING 

the  passage  of  current  across  the  joint  of  the  edges.  The 
metal  should  be  welded  soon  after  pickling,  as,  no  matter  how 
carefully  it  may  be  washed,  oxidation  is  always  sure  to  start 
very  shortly  after  the  brass  has  been  removed  from  the  pickling 
acid. 

Steel,  to  be  successfully  seam  welded,  should  not  have  a 
carbon  content  of  over  0.15  per  cent.,  for  a  higher  carbon  steel 
than  this  has  a  tendency  to  crystallize  at  the  point  of  weld, 
due  to  the  rapid  cooling  of  the  welded  portion  from  the  sur- 
rounding cold  meta!  After  welding,  the  joint  will  be  found 
to  be  about  one-third  thicker  than  the  single  thickness  of  the 
metal.  It  is  possible,  by  applying  more  pressure,  to  reduce  this 
finished  thickness  still  more,  but  it  wears  more  on  the  copper 
roller  to  do  so. 

In  welding  brass,  a  soft,  annealed  metal  should  be  used, 
for  although  hard-rolled  brass  can  be  welded,  it  does  not  force 
the  two  edges  together  very  much  and  the  finished  joint  under 
these  conditions  is  almost  twice  the  original  metal  thickness. 
However,  with  a  soft,  annealed  brass  the  finished  joint  will 
be  not  over  a  third  greater  than  the  single  metal  thickness, 
and  by  applying  sufficient  pressure  can  be  reduced  down  to  be 
not  over  10  per  cent,  thicker. 

The  principal  advantage  of  electric  seam  welding  is  that 
no  spelter  and  no  flux  are  required,  the  metal  itself  forming 
its  own  cohesive  properties,  which  allows  great  speed  in  produc- 
tion. The  greatest  efficiency  of  a  seam  welding  machine  lies 
not  only  in  its  welding  qualities  but  in  the  use  of  a  suitable 
jig  to  properly  hold  the  work.  The  jig  used  should  be  made 
so  as  to  enable  the  operator  to  place  or  remove  the  work  in 
the  shortest  possible  time,  since  the  welding  itself  is  very  fast 
compared  with  any  other  known  method  of  making  a  con- 
tinuous joint. 

In  order  that  their  seam  welding  machines  may  operate  in 
every  installation  with  the  highest  efficiency  possible,  the  Thom- 
son Electric  Welding  Co.,  Lynn,  Mass.,  build  them  standard 
only  up  to  a  certain  point  and  then  design  a  special  holding 
jig  to  best  fit  the  work  to  be  done  in  each  individual  case. 
The  amount  of  lap  allowed  in  making  lap  seam  welds  is  usually 
about  twice  the  single  sheet  thickness  of  the  metal. 

The  operation  of  a  lap  scam  welding  machine  is  very  sim- 


ELECTRIC  SEAM   WELDING 


367 


pie,  once  the  machine  is  set  for  any  given  piece  of  work  for 
which  a  special  jig  has  been  built.  After  placing  the  piece  in 
the  jig  and  securely  locking  it  there,  the  operator  depresses 
a  foot-treadle  which  throws  in  a  clutch  and  starts  the  copper 
roller  across  the  work.  By  the  proper  setting  of  adjustable 
control-stops  on  the  control-rod  at  the  top  of  the  machine, 
the  current  is  automatically  turned  on  as  the  roller  contacts 


FIG.  309. — Model  306  Lap  Seam  Welding  Machine. 

with  the  overlapping  edges  of  the  piece  to  be  welded  and  is 
automatically  turned  off  when  the  roller  reaches  the  end  of 
its  stroke;  another  stop  reverses  the  travel  of  the  roller  and 
brings  it  back  to  the  starting  position.  The  control-stops  may 
be  adjusted  to  turn  the  current  on  or  off  at  any  point  along 
the  stroke  of  the  roller  for  doing  work  with  a  seam  shorter 
than  the  maximum  capacity  of  the  machine.  The  roller  stroke 
may  be  also  shortened  so  that  the  complete  cycle  of  operation 


368 


ELECTRIC   WELDING 


will  be  accomplished  in  the  shortest  space  of  time  on  seams 
shorter  than  maximum  seam  capacity  of  any  machine.  In 
order  to  keep  the  copper  roller  from  overheating  in  action, 
water  is  introduced  through  its  bronze  bearings  on  each  side. 
This  same  water  circulation,  also  passes  through  the  under 
copper  horn  or  mandrel  and  then  through  the  cast-copper 
secondary  of  the  transformer,  so  that  the  machine  can  be 
operated  continually,  24  hours  per  day  if  desired,  without 
overheating. 

Lap    Seam   Welding   Machines. — The    lap    seam    welding 


FIG.  310.— Details  of  Welding  Roller  Head. 

machine,  known  as  Model  306,  shown  in  Fig.  309  will  weld 
a  seam  6  in.  long  in  soft  iron  or  steel  stock  up  to  20  gage 
in  thickness,  or  brass  and  zinc  up  to  24  gage  thick.  This 
machine  will  make  from  60  to  600  welds  per  hour,  depending 
on  the  nature  of  the  work  and  the  quickness  with  which  the 
pieces  can  be  placed  in  and  removed  from  the  jig.  The  copper 
horn  is  water-cooled  and  has  an  inserted  copper  track  on 
which  the  work  rests.  The  upper  contact  consists  of  a  copper 
roller  6^  in.  in  diameter,  mounted  on  a  knockout  shaft  sup- 


ELECTRIC  SEAM  WELDING 


369 


ported  in  water-cooled  bearings.  Pressure  is  exerted  on  the 
copper  roller  by  means  of  a  series  of  springs  on  each  side 
which  are  adjustable  to  give  the  proper  tension  for  various 
thicknesses  of  stock.  Current  control  is  automatic  through 
a  magnetic  wall  switch  carrying  the  main  current.  The  latter 
is  controlled  from  a  mechanical  switch  which  is  thrown  in  or 
out  by  the  action  of  the  roller-carrying  mechanism  as  it  starts 


FIG.  311. — Thomson  No.  318  Lap  Seam  Welding  Machine. 


and  completes  the  stroke  for  which  it  is  set.  Standard  wind- 
ings are  for  220-,  440-,  and  550-volt,  60-cycle,  alternating  cur- 
rent. Current  variation  for  different  thicknesses  and  kinds 
of  stock,  is  effected  through  a  regulator  which  gives  50  points 
of  voltage  regulation.  A  variable-speed  J-hp.  motor  gives  a 
wide  variation  in  the  speed  with  which  the  roller  may  be  fed 
over  the  work.  The  standard  ratings  for  the  machine  are 
15  kw.  or  25  kva.,  with  60  per  cent,  power  factor.  This 


370 


ELECTRIC   WELDING 


machine  covers  32X96  in.  floor  space,  is  68  in.  high  and  weighs 
2750  Ib. 

A  close-up  view  of  the  type  of  roller-carrying  head  used 
on  all  the  lap  seam  welding  machines,  is  shown  in  Fig.  310. 
In  this  view  the  roller  is  shown  operating  between  the  clamping 
bars  of  a  special  holding  jig  on  the  horn.  As  the  roller  itself 
occasionally  requires  smoothing  off  around  its  contacting  sur- 
face, its  bearing  has  been  designed  to  knock  out  quickly  so 


FIG.  312. — Large  Size,  No.  324,  Lap  Seam  Welding  Machine. 

that  removal  and  replacement  of  the  roller  is  very  simple  and 
easy  to  accomplish.  The  cleaner  the  stock  being  welded  is 
kept,  the  longer  a  roller  will  operate  without  requiring  smooth- 
ing off,  as  dirt  and  scale  on  the  stock  cause  a  slight  sparking 
as  the  roller  passes  along,  which  tends  to  pit  up  its  contact 
surface. 

The  machine  shown  in  Fig.  311,  known  as  Model  318,  is 
a  larger  and  heavier  machine  than  the  one  previously  described 


ELECTRIC  SEAM  WELDING 


371 


and  will  weld  a  lap  scam  18  in.  long  on  the  same  gages  of 
metal  quoted.  Another  very  similar  but  smaller  machine 
(Model  312)  is  also  made  for  welding  seams  up  to  12  in. 

In  Fig.  312  is  seen  a  considerably  larger  machine,  Model 
324,  capable  of  welding  a  lap  seam  up  to  24  in.  in  length. 
The  production  is  from  30  to  120  welds  per  hour.  The  machine 
covers  a  floor  space  of  36X90  in.,  is  72  in.  high,  and  weighs 
3500  Ib.  All  other  specifications  are  the  same  as  given  for 
Fig.  309. 

Examples  of  Holding1  Jigs. — The  machines  shown  may  be 
fitted  with  numerous  forms  of  holding  jigs  from  the  simple 


FlG.  313. — Oil  Stove  Burner  Tubes  Before  and  After  Welding. 

bar  clamps  shown  on  the  horns  in  Figs.  311  and  312,  to  various 
more  complicated  forms,  some  of  which  may  be  mounted  on 
the  knee  below  the  horn  or  bolted  direct  to  the  face  of  the 
machine  column. 

The  small  oil  stove  burner  tubes  shown  in  Fig.  313  lend 
themselves  nicely  to  the  seam  welding  process.  Cylindrical 
pieces  such  as  the  shell  tubes  for  automobile  mufflers  shown 
in  Fig.  314,  need  a  rather  elaborate  holding  jig.  A  machine 
fitted  up  for  this  work  is  shown  in  Fig.  315.  To  insert  a 
muffler  shell  into  this  jig  the  hinged  end  is  swung  outward 
and  downward;  the  two  halves  of  the  holder  are  spread  apart 
by  pressing  down  on  the  left-handle  treadle;  the  shell  is  then 


372 


ELECTRIC   WELDING 


thrust  into  the  holder;  the  treadle  is  released,  which  allows 
the  holder  sides  to  be  pressed  in  by  the  springs  and  hug  the 
muffler  shell  around  the  horn  of  the  machine,  with  the  edges 
overlapping  enough  for  the  weld;  the  end  gate  is  then  closed 
and  the  welding  roller  started  over  the  seam.  The  principal 
function  of  the  gate  is  to  hold  the  muffler  shell  square  in  the 
jig  and  prevent  it  behig  pushed  out  by  the  welding  roller. 


FIG.  314. — Seam  Welded  Automobile  Muffler  Tubes. 

A  jig  for  holding  large  cans  is  shown  in  Fig.  316.  The 
side  clamps  of  this  jig  are  operated  by  means  of  the  lever 
shown  at  the  left.  An  end  gate,  shown  open,  is  used  in  the 
same  way  as  in  the  muffler  shell  jig.  Work  of  this  kind  is 
of  course  much  slower  than  with  a  smaller  jig,  yet  it  is  faster 
than  by  any  other  process  of  closing  the  scams. 


ELECTRIC  SEAM   WELDING 


373 


Bucket  bodies  are  held  as  shown  in  Fig.  317.  The  holding 
jig  is  made  to  slide  in  a  channel  bolted  to  the  machine  knee. 
The  jig  is  slid  back  clear  of  the  horn  and,  with  the  gate  in 
the  flaring  end  open,  the  bucket  blank  is  inserted.  The  gate 


FIG.  315. — Holding  Jig  for  Automobile  Muffler  Tubes. 

is  then  closed  by  means  of  the  handle,  the  jig  and  work  is 
pushed  over  the  horn  to  a  stop,  and  the  weld  is  made  as  usual. 
Another  application  of  seam  welding,  is  to  use  it  for  welding 
the  ends  of  strip  stock  together,  end  to  end,  so  as  to  facilitate 
continuous  passage  of  the  strip  through  the  dies  of  a  punch 
press.  A  machine  fitted  up  for  this  work  is  shown  in  Fig.  318. 


374  ELECTRIC   WELDING 

The  ends  of  the  two  strips  to  be  welded  are  inserted  in  the 
jig  from  opposite  sides  and  the  edges  brought  together.  The 
pieces  are  then  clamped  by  means  of  the  two  levers  shown  in 
front  of  the  jig,  which  operate  eccentrics  over  the  clamping 


FIG.  316. — Holding  Jig  for  Large  Sheet  Metal  Cans. 

plates.     The  welding  roller  is  then  run  over  the  ends  as  in 
other  work  of  this  kind. 

Flange  seam  welding  differs  from  lap  seam  welding  in 
that  instead  of  the  metal  being  lapped  a  slight  fin  or  flange 
is  formed  along  the  edges  of  the  metal  parts,  the  flanges  being 
welded  together  and  practically  eliminated  in  the  process.  This 


ELECTRIC  SEAM  WELDING 


375 


Class  of  welding  is  especially  adapted  to  the  manufacture  of 
light  gage  coffee  and  teapots  spouts  or  similar  work. 

A  machine  built  especially  for  flange  seam  welding,  known 


FIG.  317. — Jig  for  Holding  Bucket  Bodies. 

as  Model  26,  is  shown  in  Fig.  319.  The  work  being  done  is 
the  welding  of  the  two  halves  of  teapot  spouts.  In  the  operation 
the  two  halves  of  the  spout  are  clamped  securely  in  a  special 
copper  jig,  Fig.  320,  which  has  been  carefully  hand-cut  to 


376 


ELECTRIC  WELDING 


fit  the  halves  of  the  spout  perfectly  on  the  entire  contacting 
area.  The  jig  is  pushed  around  on  the  flat  copper  table,  which 
constitutes  the  top  of  the  welding  machine,  so  that  the  seam 
of  the  edge  to  be  welded  is  allowed  to  ride  along  the  small 


FIG.  318. — Jig  for  Welding  Ends  of  Metal  Strips  Together. 

power-driven  copper  roller  which  is  mounted  on  a  vertical 
shaft,  as  illustrated  in  Fig.  321.  The  halves  which  are  welded 
by  this  process  must  be  blanked  out  by  special  steel  dies  to 
give  the  correct  amount  of  fin  or  flange  on  each  edge.  This 


ELECTRIC  SEAM   WELDING 


377 


fin  is  heated  to  the  plastic  stage  by  contact  with  the  roller 
and  the  slight  pressure  applied  not  only  forces  the  metal  of 
the  two  fins  to  cohere  but  also  forces  the  projection  into  a 
level  with  the  outer  surface  of  the  spout,  thus  giving  a  finished 
job  direct  from  the  welder  which  is  smooth  enough  without 


FIG.  319. — Machine  for  Flange  Seam  Welding. 

any  grinding  to  be  ready  for  the  enamelling  or  agate-coating 
process. 

The  secret  of  success  of  this  work  lies  wholly  in  the  proper 
preparation  of  not  only  the  copper  holding-dies,  but  also  the 
steel  flanging  and  forming  dies.  A  finished  spout,  just  as  it 


378 


ELECTRIC   WELDING 


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ELECTRIC  WELDING 


FIG.  320. — Jig  for  Holding  Teapot  Spouts  for  Welding. 


FIG.  321. — Diagram  of  Flange  Seam  Welding  Operation. 


FIG.  322. — A  Finish  Welded  Teapot  Spout. 


ELECTRIC  SEAM   WELDING  381 

comes  from  the  welding  machine,  is  shown  in  Fig.  322.  The 
welded  seam  is  barely  visible. 

In  order  to  assist  those  who  have  welding  jobs  to  do,  to 
calculate  the  current  cost  on  various  jobs,  Table  XXVIII  is 
given.  This  table  shows  the  approximate  current  consumption, 
and  multiplying  the  rate  given  by  the  local  rate  charged,  the 
cost  of  1000  welds  can  be  easily  ascertained. 

Table  XXIX  is  very  convenient  for  ascertaining  the  size 
of  copper  wire  needed  to  connect  the  different  machines  men- 
tioned to  the  main  source  of  current  supply. 


CHAPTER   XVII 

MAKING    PROPER    RATES    FOR    ELECTRIC    WELDING 
AND  THE  STRENGTH  OF  WELDS 

The  uncertainty  which  seems  to  exist  regarding  electric 
welding  rates  among  central-station  interests,  says  S.  I. 
Oesterreicher  in  Electrical  World,  is  no  doubt  due  to  the  indif- 
ference of  the  welding  industry,  which  during  a  long  period 
in  the  past  did  not  assist  those  affected  by  the  rates  as  much 
as  its  unquestionable  duty  would  have  suggested. 

While  welding  installations  of  only  comparatively  small 
sizes  had  to  be  considered — say  from  25  to  100  kva. — no  great 
harm  was  done  by  such  tactics  to  either  interest.  However, 
with  the  installation  of  large  equipments  and  the  operation 
of  large  unit  welding  machines,  central  stations  suddenly 
experienced  disturbances  upon  their  lines  and  in  their  stations, 
which  were  anticipated  but  partly  and  were  blamed  entirely 
upon  the  welding  equipment.  Thus,  to  protect  themselves, 
central-station  interests  launched  into  a  partially  retroactive 
policy,  greatly  to  the  detriment  of  the  welding  industry  as 
a  whole. 

Since  welding  installations  of  several  thousand  kva.  capacity 
are  not  unusual,  it  is  proper  that  all  points  of  doubt  should 
be  considered  as  broadly  and  fairly  as  possible,  and  a  far- 
reaching  co-operative  policy  inaugurated.  The  revenue  from 
such  large  installations  may  easily  reach  several  thousand 
dollars  a  month.  It  is  therefore  obvious  that,  from  a  purely 
commercial  standpoint,  a  welding  load  is  a  very  desirable 
constant  source  of  income  to  the  central  station. 

Looking  at  the  reverse  side,  it  should  be  recalled  that  cen- 
tral-station engineers,  on  account  of  past  sad  experiences,  had 
jumped  to  the  following  conclusions : 

1.  That  a  welding  installation  is  a  very  unreliable  metering 
proposition. 

382 


MAKING   PROPER  RATES   FOR  ELECTRIC   WELDING     383 

2.  That  it  has  a  poor  load  factor. 

3.  It   has  a   constantly  fluctuating  load  varying   between 
extreme  limits,  and 

4.  It  has  a  bad  power  factors 

The  first  important  point  is,  no  doubt,  the  metering.  The 
time-honored  opinion  on  one  side  that,  due  to  the  short  period 
involved,  an  integrating  wattmeter  does  not  respond  quickly 
enough,  is  contradicted  by  the  claim  on  the  other  side  that 
the  deceleration  of  the  meter  disk  compensates  for  the  lagging 
acceleration.  As  far  as  the  writer  is  aware,  not  the  slightest 
positive  proof  has  been  offered  to  support  either  contention. 
Considering  for  instance  a  200-volt,  300-amp.,  single-phase, 
two-wire  wattmeter,  whose  disk  at  full  load  makes  25  r.p.m., 
and  assuming -the  total  energy  consumption  to  be  integrated 
within  0.2  second,  it  will  be  found  that  to  register  correctly 
the  meter  disk  has  to  travel  about  0.08  of  a  revolution.  It  is 
scarcely  possible  that  by  merely  looking  upon  a  meter  disk 
any  one  could  guess  within  100  per  cent  the  actual  travel 
during  such  a  short  time  interval.  A  stop  watch  will  scarcely 
be  of  any  assistance;  neither  will  a  cycle  recorder  with  an 
ammeter  and  voltmeter  check  be  of  any  value,  since  no  instru- 
ment is  of  such  absolute  dead  beat  as  to  come  to  rest  from 
no  load  to  full  load  within  0.2  second.  Such  methods  therefore 
are  of  no  value  in  ascertaining  the  behavior  of  a  wattmeter 
under  sudden  intermittent  heavy  loads. 

The  next  step  of  the  metering  proposition  was  to  take  the 
rated  energy  consumption  of  the  welding  machine  as  given  by 
the  manufacturer,  assume  a  certain  load  factor,  calculate  from 
these  data  the  energy  consumption,  correct  for  the  power  factor 
and  check  the  answer  periodically  on  the  meter  dial.  The 
result  obtained  on  the  meter  was  usually  a  constantly  varying, 
lower  energy  consumption  than  calculated,  and  no  doubt  this 
was  the  cause  of  the  great  distrust  of  the  meter.  This  method 
is  worse  than  no  check  at  all,  and  it  is  so  for  the  following 
reasons : 

1.  The  energy  consumption  at  a  welder  depends  upon  the 
welding  area  of  the  metal,  but  is  not  a  proportionate  variable. 
That  is,  all  other  factors  being  the  same,  two  square  inches 
of  a  certain  weld  do  not  consume  twice  as  much  energy  as 
one  square  inch  does.  Fig.  323  shows  this  fact  plainly.  It 


384 


ELECTRIC   WELDING 


is  also  of  common  knowledge  that  on  a  spot  welder  the  area 
of  the  weld  varies  from  weld  to  weld  just  as  much  as  the 
electrode  contact  area  does.  Assuming  an  electrode  at  the  start 
as  Vie  in-  diameter  at  the  tip,  after  about  200  welds  it  might 
be  anything  from  J  in.  to  5/i6  in-  diameter,  thus  gradually 
increasing  its  contact  area  anywhere  from  75  per  cent  to  175 
per  cent. 

2.  On  butt  welders  the  energy  consumption  does  not  depend 


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FIG.  323. — Energy   Consumption  of  Resistance  Welding  for  Commercial 
Grades  of  Sheet  Iron. 

upon  the  size  of  the  weld  alone,  but  also  upon  the  clamping 
distances.  Fig.  324  gives  some  information  about  the  influence 
of  variable  clamping  distances  upon  the  energy  consumption 
of  welding  machines.  On  a  butt  welder,  the  clamping  distances 
increase  with  the  gradual  wear  of  the  electrode ;  thus  the  above 
spot  welder  conditions  are  duplicated  on  butt  welders  also. 
3.  If  no  compensation  is  made  to  vary  the  impressed  ernf. 


MAKING  PROPER   RATES   FOR  ELECTRIC   WELDING     385 

of  the  welder — and  this  is  never  done — then  the  time  must 
vary  from  weld  to  weld  according  to  the  condition  of  the 
electrode.  If  the  time  is  changing  constantly,  the  assumed 
load  factor  changes  correspondingly;  thus  there  are  three  con- 
stantly changing  factors  in  the  estimated  energy  consumptions, 
beyond  any  reasonable  approximation  of  the  actual  facts. 

A  more  reliable  method  would  be  a  periodic  oscillograph 
test,  but  this  method  is  rather  complicated  and  expensive  and 
could  be  done  only  by  large  central  stations  which  have  both 
the  equipment  and  the  trained  personnel  for  such  work. 

Such  tests,  once  they  are  made  for  certain  types  of  welders 


3.5         4.0 
Inches 


1.0          1.5          2.0         2.5          3.0 
Clamping     Distance 

,FiG.  324. — Effect    of   Clamping   Distance   Between    Electrodes    Upon    Time 
and  Energy  Demand.     Area,  0.25  Sq.  In. 

and  work,  will  give  excellent  data  from  which  to  check  the 
actual  behavior  of  the  standard  type  of  wattmeter.  If  such 
comparisons  are  made,  it  will  be  found  that  the  integrated 
energy  consumption  of  the  wattmeter  will  be  larger  than  the 
oscillograph  test  indicates.  It  is  not  intended  to  claim  that 
the  wattmeter  registers  "fast. "  Laboratory  tests  are  usually 
made  by  skilled  men,  who  before  the  test  carefully  ascertained 
all  important  factors  entering  into  the  test,  as  area  of  weld, 
condition  of  electrodes,  welder,  emf.,  cleanliness  of  material, 
etc.,  whereas  under  normal  operating  conditions  almost  no 
attention  is  paid  by  the  operator  to  these  considerations.  In 
fact,  if  the  operator  works  on  a  piecework  or  bonus  basis,  he 
will  conceal  as  much  as  possible  all  discrepancies  which  have 


386  ELECTRIC  WELDING 

a  tendency  even  temporarily  to  curtail  his  earnings.  The  result 
of  his  policy  has  a  very  important  effect  upon  the  wattmeter. 

Summing  up  the  metering  proposition  and  speaking  from 
experience  on  large  welding  installations  with  capacities  over 
250,000  sq.  in.  of  welding  per  month,  where  ten  to  fifteen  butt 
welding  machines  are  constantly  thrown  on  or  off  the  supply 
circuit,  it  is  safe  to  claim  that  in  such  installations  the  standard 
alternating-current  integrating  wattmeter  is  on  the  job. 

The  Load  Factor. — The  present-day  tendency  in  resistance 
welding  practice  is  to  perform  the  weld  as  quickly  as  possible 
without  injury  to  the  metal,  but  fast  enough  to  prevent  im- 
perfection at  the  weld.  Having  in  mind  large  welders  with 
5  to  15  sq.  in.  weld  capacities,  this  tendency  will  give  a  unit 
load  factor  not  much  over  10  per  cent  per  welder.  From  the 
central-station  viewpoint,  this  factor  is  certainly  very  low  and 
undesirable. 

However,  two  important  circumstances  alter  the  condition 
considerably.  The  first  point  is  that  in  large  installations  one 
large  welder  will  not  suffice  to  do  all  the  required  work,  there- 
fore several  will  have  to  be  installed.  Owing  to  the  big  energy 
demands  these  large  welders  never  operate  simultaneously. 
While  one  welds  the  next  is  cleaned,  the  third  is  prepared,  the 
fourth  is  waiting  for  the  signal  to  weld,  etc. ;  thus  the  load 
factor  of  the  installation  as  a  whole  is  considerably  over  10 
per  cent  and  nearer  to  20  per  cent.  Another  natural  circum- 
stance of  large  installations  is  the  fact  that  not  all  work  requires 
large  welders.  There  are  usually  ten  to  fifteen  smaller  welders 
installed,  of  which  30  per  cent  might  work  intermittently  with 
the  larger  welders.  Thus  it  will  be  seen  that  the  load  factor 
is  bad  only  in  small  installations  connected  to  small  central 
stations,  while  large  installations,  which  necessarily  must 
receive  their  supply  of  energy  from  comparatively  larger  cen- 
tral plants,  have  rather  a  good  aggregate  load  factor,  reaching 
well  up  to  25  to  30  per  cent. 

Another  point  for  consideration  is  the  fact  that,  owing  to 
its  temperature,  large  work  cannot  be  handled  immediately 
after  welding.  The  work  must  cool  off  before  additional  opera- 
tions can  be  performed  upon  it.  The  cooling  takes  some  time. 
In  several  instances  it  was  found  desirable  to  shift  the  working 
hours  of  the  welding  crew  several  hours  ahead  or  behind  the 


MAKING   PROPER  RATES   FOR  ELECTRIC  WELDING     387 

working  hours  of  the  rest  of  a  factory,  for  the  sole  reason  that 
there  should  be  on  hand  sufficient  cool  welded  work  for  the 
successive  manufacturing  steps.  If  this  time-shifting  is  selected 
to  coincide  with  the  low-point  period  of  the  load  factor  of  a 
central  station,  then  there  results  an  actual  all-around  improve- 
ment. For  this  the  welding  installation  should  be  entitled  to 
a  certain  proportionate  consideration. 

Maximum  Demand. — Owing  to  the  instantaneous  severity 
of  a  welding  load,  demand  upon  a  supply  station  seems  to  be 
of  considerable  importance.  However,  the  shifting  of  a  load 
factor  toward  an  off-load  period,  as  described,  will  certainly 
take  the  severest  effects  off  the  system.  Under  such  conditions 
regulation  of  the  supply  system  suffers  only  in  small  plants, 
and  only  in  places  where  lighting  and  power  loads  are  fed 
from  the  same  mains 

But  large  welding  installations  are  usually  direct-connected 
through  transformer  banks  to  the  station  buses,  where  the 
fluctuating  character  of  the  welding  load  will  be  almost  negli- 
gible and  certainly  will  not  affect  the  regulation  of  a  system 
in  a  degree  commensurate  with  the  size  of  the  connected  weld- 
ing installation.  Of  course  in  all  these  discussions  it  is  assumed 
that  the  station  apparatus,  transformers  and  supply  feeders 
are  properly  selected,  with  equipment  properly  calculated  to 
fit  the  particular  welding  load.  In  the  past  this  has  not  always 
been  the  case,  and  this  is  one  of  the  causes  of  so  many  different 
maximum  demand  charges. 

The  ratio  which  the  maximum  demand  should  bear  to  the 
connected  load  will  always  remain  a  local  issue  between 
producer  and  consumer.  The  ratio  should,  however,  be  made 
to  depend  on  the  average  kilovolt-ampere  energy  demand  of 
all  the  welders  (and  not  on  their  rated  capacities  as  given 
by  the  manufacturer)  and  of  the  rated  capacity  of  the  primary 
supply  installation.  If  the  welding  customer  bears  a  part  of 
the  installation  charges  caused  by  larger  transformers  and 
larger  supply  mains,  he  should  benefit  by  the  resultant  mutual 
advantages.  However,  no  demand  charge  should  be  based 
upon  a  mixed  welding  and  motor  load  supplied  from  a  common 
primary  installation.  The  importance  of  this  claim  will  be 
more  evident  if  it  is  stated  that  by  separating  a  certain  mixed 
welding  and  motor  circuit,  and  by  installing  an  additional 


388  ELECTRIC  WELDING 

100-kw.  equipment,  the  maximum-demand  charge  in  a  single 
supply  circuit  in  one  month  was  reduced  over  $200. 

To  be  sure  that  no  more  disturbing  overloads  are  thrown 
upon  the  line  than  have  been  contracted  for,  overload  relays, 
time  clocks  and  maximum-demand  indicators  will  be  found 
sufficiently  reliable  for  all  honest  purposes  on  both  sides  of 
the  controversy. 

Proper  grouping  of  the  single-phase  welding  loads  upon 
a  three-phase  supply  system  will  give  perfect  satisfaction  in 
almost  all  installations  but  those  of  small  size. 

Power  Factor. — So  much  has  been  said  and  so  much  worry 
caused  about  the  poor  power  factor  of  a  welding  installation 
that  it  is  now  universally  accepted  that  the  power  factor  is 
bad,  and  nothing  further  is  done  about  it.  The  outstanding 
feature  about  this  condition  is  that  the  central  stations,  in  a 
most  unfortunate  moment,  decided  to  t( penalize"  the  power 
factor.  It  is  not  the  charge  for  the  condition,  but  the  adoption 
of  the  word  for  the  charge,  which  makes  the  customer  balk 
and  is  the  cause  of  no  end  of  distrust  toward  the  welding 
machine.  The  word  "penalty"  conveys  to  the  lay  mind  the 
impression  that  a  poor  power  factor  exists  only  with  welding 
installations,  and  naturally  the  conclusions  are  not  nattering 
for  the  welding  equipment. 

No  attempt  is  made  here  to  describe  the  well-known  methods 
of  improving  the  power  factor  of  a  welding  installation  with 
synchronous  apparatus.  The  adoption  of  such  methods  is  more 
of  a  commercial  than  an  engineering  problem.  Upon  investiga- 
tion it  will  be  found  that,  with  few  exceptions,  it  is  cheaper 
to  pay  for  the  poor  power  factor  than  to  invest  in  additional 
apparatus.  However,  the  average  power  plant  usually  has, 
besides  a  welding  installation,  a  number  of  other  consumers, 
the  effects  of  whose  poor  power  factor  are  felt  in  considerable 
measure  at  the  generators.  If  all  such  sources  are  investigated 
and  segregated  upon  one  common  bus,  together  with  a  welding 
load,  it  might  be  found  that  either  a  synchronous  or  static 
apparatus  would  more  than  pay  for  itself,  if  installed  at  the 
proper  place. 

If  this  fact  is  explained  to  a  welding  customer,  there  can 
be  no  doubt  that  he  will  be  only  too  eager  to  bear  a  certain 
proportion  of  the  investment  for  a  special  apparatus  and  thus 


MAKING   PROPER  RATES   FOR  ELECTRIC   WELDING     389 

secure  for  himself  a  better  rate  for  the  consumed  energy.  With 
proper  co-operation  between  the  central  station  and  the  welding 
customer  on  all  these  points  of  mutual  interest,  much  misunder- 
standing and  distrust  could  be  eliminated,  benefiting  all  parties 
concerned  in  the  welding  industry. 


FILLET  AND  SPOT  WELDED 


FILLET  WELDED 


Y& 


RIVETED  AND  FILLET  WELDED 


SPOT  WELDED 
12" 


&r 


3/4  Rivets 


»/2 


E    Pfr 

-f        4-    .I" 

-^-^ 

:«4        !'... 

: 

RIVETED  JOINT 
FIG.  325.— Welded  and  Riveted  Joints. 

Strength  of  Resistance  Welds.— In  some  of  its  applica- 
tions, spot  welding  affords  a  method  of  preliminary  joining 
ship  hull  plates,  after  which  the  required  additional  strength 
is  obtained  by  arc  welding.  The  Welding  Research  Sub-Com- 
mittee made  some  progress  in  comparing  combined  spot  and 


390 


ELECTRIC  WELDING 


arc  welds,  and  combined  rivet  and  arc  welds  with  riveted, 
spot- welded  and  arc-welded  joints.  It  is  not  a  question  in 
such  an  investigation,  of  spot  versus  arc  welding,  but  of  spot 
and  arc  welding. 

According  to  Hobart,  test  specimens  are  made  up  of  the 
following  combinations : 

(a)   Spot  and  fillet  welds  (two  samples  made) 


123456 


7         8        9        1O 


FIG.  326. — Spot-Welding  Tests  on  Hoop  Iron. 

(b)  Fillet  welds,  made  by  welding  fillets  about  two  inches 

in  length  at  the  ends  of  overlapping  plates   (two 
samples  made) 

(c)  Rivet  and  fillet  welds  (one  sample  made) 

(d)  Spot  welds,  made  by  welding  two  spots  approximately 

one  inch  in  diameter,  on  the  plates   (two  samples 
made) 

(e)  Riveted  joint,  made  by  riveting  a  £X4X12  in.  plate 

with  two  plates  JX4X16  in.,  using  two  f  in.  rivets 
and  a  four  inch  plate  lap  (one  sample  made) 


MAKING  PROPER  RATEG  FOR  ELECTRIC  WELDING     391 

The  way  these  plates  were  fastened  is  illustrated  in  Fig. 
325.  The  results  of  the  tests  were  as  follows : 

(a)  Spot  and  fillet  weld ultimate  load 50,350  Ib. 

(b)  Fillet  welds ultimate  load 37,000  Ib. 

(c)  Eivet  and  fillet  welds ultimate  load 35,000  Ib. 

(d)  Spot  welds    ultimate  load 28,000  Ib. 

(e)  Riveted  joint    ultimate  load 13,000  Ib. 

Spot- Welding  Tests  on  Hoop  Iron. — The  Thomson  Co.  made 
up  ten  samples  of  spot-welded,  riveted,  butt-welded  and  plain 
pieces  of  hoop  iron,  and  had  them  tested  in  the  Lunkenheimer 
laboratory.  The  pieces  after  testing  are  shown  in  Fig.  326. 

The  results  were  as  follows: 

No.     1.  Spot- welded  in  one  place — broke  at  weld  at  1,625  pounds. 

No.     2.  Spot-welded    in    two    places,    also    two    rivets — broke    at    rivets    at 

1,555  pounds. 
No.     3.  Spot-welded  in  three  places: — broke  outside  weld  at  2,715  pounds. 

(Notice  elongation  of  metal.) 
No.     4.  Spot-welded  in  three  places,  also  three  rivets — broke  at  rivets  at 

2,055  pounds. 

No.     5.  Solid  lap-weld — broke  outside  weld  at  2,720  pounds. 
No.     6.  Butt-welded — broke  at  weld  at  2,555  pounds. 
No.     7.  Spot-welded  in  one  place,  and  riveted  once — broke  at  rivet  at  990 

pounds. 

No.     8.  Solid  lap-weld — broke  at  weld  at  2,425  pounds. 
No.     9.  Spot-welded  in  two  places — broke  at  weld  at  2,275  pounds. 
No.  10.  Plain  piece  of  hoop  iron,  not  welded — pulled  apart  at  2,690  pounds. 

Taking  the  average  of  the  breaking  points  of  the  three 
pieces,  3,  5  and  10,  that  broke  in  the  pieces  themselves,  we 
get  approximately  2700  Ib.  as  the  strength  of  the  hoop  iron. 
This  furnishes  a  basis  for  percentage  calculations  if  such  are 
desired.  By  grouping  six  of  the  tests,  we  get  the  following 
results  for  comparative  purposes: 

Test  No.  1.     One  Spot-weld:   broke  at  1,625  pounds. 
Test  No.  7.     One  Rivet:  broke  at  990  pounds. 

The  weld  stood  over  60  per  cent  more  than  the  rivets 
Test  No.  9.     Two  Spot-Welds:   broke  at  2,275  pounds. 
Test  No.  2.     Two  Rivets:   broke  at  1,555  pounds. 

The  weld  stood  over  60  per  cent  more  than  the  rivets. 
Test  No.  3.  Three  Spot-Welds:  broke  outside  weld  at  2,715  pounds. 
Test  No.  4.  Three  Rivets:  tore  apart  at  2,055  pounds. 


392 


ELECTRIC  WEEDING 


Strength  of  Spot- Welded  Holes.— It  sometimes  happens  that 
a  hole  will  by  mistake  be  punched  in  a  plate  where  it  is  not 
needed.  The  spot  welder  can  be  used  to  plug  such  holes  and 
make  the  plate  as  strong  as,  or  stronger  than,  it  was  originally. 
It  is  first  necessary  to  make  a  plug  of  the  same  material  as 
the  plate  which  will  fit  in  the  hole  and  which  is  slightly  longer 
than  the  plate  is  thick.  The  length  required  will  depend  on 
the  snugness  of  the  fit  of  the  plug  in  the  hole;  there  should 
be  enough  metal  in  the  plug  to  a  little  more  than  completely 
fill  the  hole.  The  plate  is  placed  in  the  welder  with  the  hole 
which  is  to  be  filled  centered  between  the  electrodes,  the  plug 
is  placed  in  the  hole,  the  electrodes  brought  together  upon  it, 


J?IG.  327. — Sample  Plates  with  Holes  Plugged  by   Spot- Welding.     At  the 
Eight  Is  Shown  a  Plate  with  Plug  in  Place  Previous  to  Welding. 

and  upon  the  application  of  pressure  and  current  the  plug 
will  soften,  fill  the  hole,  and  weld  to  the  plate. 

Fig.  327  shows,  at  the  extreme  right,  a  piece  of  ^-in.  plate 
with  a  punched  hole  which  is  to  be  plugged,  and  the  plug  in 
place  previous  to  welding.  The  three  pieces  at  the  left  of 
the  photograph  have  the  plugs  welded  in  place.  A  fact  which 
the  illustration  does  not  bring  out  very  clearly  is  that  the 
surface,  after  the  plug  is  fused  in,  is  practically  as  smooth  as 
the  remainder  of  the  plate,  the  maximum  difference  in  thick- 
ness between  the  plugged  portion  and  the  remainder  of  the 
plate  being  not  more  than  1/32  in.  on  a  J-in.  plate. 

That  there  is  a  real  and  complete  weld  between  the  plug 
and  the  plate  is  shown  by  Fig.  328.  The  four  samples  illus- 


MAKING  PROPER  RATES  FOR  ELECTRIC  WELDING     393 

trated  were  placed  in  a  testing  machine  and  broken  by  longi- 
tudinal pull,  with  the  interesting  result  that  not  one  of  the 
three  plugged  plates  broke  through  the  weld.  The  sample  at 
the  right  was  broken  to  give  an  indication  of  the  strength 
of  the  samples  after  punching  and  before  welding.  Two  sam- 


I    Pi    mm 
•  •  i 


FiG.  328.— Plates  Shown  in  Fig.  327  After  Pulling  in  the  Testing  Machine. 
Note  That  All  Welded  Plates  Broke  Outside  the  Weld. 

TABLE  XXX. 


No.  of 
Sample 

Description 
of  Sample 

Sec- 
tion 
In. 

Tensile 
Strength 
Lb. 

Location 
of 
Fracture 

1 

Punched    &-in.    dia- 

2 by 

59,320 

Outside 

meter      hole      and 

1A 

weld 

plugged  by  welding 

2 

Punched    -&-in.    dia- 

2 by 

59,320 

Outside 

meter      hole      and 

H 

weld 

3 

plugged  by  welding 
Punched    i^-in.    dia- 

2 by 

59,350 

Outside 

meter      hole      and 

1A 

weld 

plugged  by  welding 

4 

Punched    -&-in.    dia- 

2 by 

31,590 

Through 

meter  hole  but  not 

1A 

hole 

plugged 

5 

Original      bar,      not 

2  by 

59,230 

Through 

punched 

H 

center 

6 

Original      bar,      not 

2  by 

59,000 

Through 

punched 

H 

center 

394  ELECTRIC   WELDING 

pies  (not  shown)  from  the  same  bar  but  without  the  punched 
holes  were  pulled  to  find  the  original  strength  of  the  material. 
The  results  are  given  in  Table  XXX. 

It  is  interesting  to  note  that  the  average  of  the  breaking 
point  of  the  three  samples  punched  and  plugged  was  59,330 
lb.,  whereas  the  average  for  the  two  samples  not  punched  was 
59,115  lb.,  or  115  lb.  less.  This  proves  that  there  was  no  weak- 
ening of  the  surrounding  plate,  due  to  the  weld.  That  the 
ductility  of  the  welded  section  was  somewhat  decreased  is 
shown  by  the  photographs  of  the  samples  after  pulling. 

The  actual  welding  time  required  for  plugging  a  hole  in 
a  plate  is  from  five  to  ten  seconds.  Of  course,  it  is  necessary 
to  have  a  plug  of  the  proper  size,  but  a  variety  of  plugs,  of 
all  the  standard  rivet  hole  diameters  and  of  lengths  suitable 
for  the  various  thicknesses  of  plates,  could  be  made  up  and 


FIG.  329. — Straight  Rods  Spot-welded  to   Angle  Iron  and  then    Bent  by 
Hammer  Blows,  the  Angle  Being  Supported  only  by  the  Un welded  Flange. 

kept  in  stock  in  the  yard.  The  method  described  should  prove 
a  valuable  means  of  salvaging  material  which  otherwise  might 
have  to  be  scrapped. 

Strength  of  Rods  Mash- Welded  to  Angle  Iron.— While  no 
figures  are  available,  the  illustration  Fig.  329  will  give  an 
idea  of  the  strength  of  welds  where  rods  are  mash-welded  to 
angle  iron  or  plate.  Three  straight  iron  rods  were  welded 
to  an  angle  iron  and  then  hammered  over  with  a  sledge,  as 
shown.  This  is  a  very  severe  test  of  a  weld. 

Strength  of  Electric  Resistance  Butt- Welds. — According  to 
Kent,  tests  of  electric  resistance  butt-welded  iron  bars  resulted 
as  follows: 

32  tests,  solid  iron  bars,  average .52,444  lb. 

17  tests,  electric   butt-welds,  average 46,836  lb. 


MAKING  PROPER  RATES  FOR  ELECTRIC  WELDING     395 

This  is  an  efficiency  of  89.1%. 

Presumably  the  welds  were  turned  to  the  size  of  the  bars, 
although  Kent  does  not  say  so. 

In  a  number  of  tests  on  draw-bench  mandrels  the  following 
results  were  obtained.  The  mandrels  consisted  of  one  piece 
of  §  in.  dia.,  30-40  point  carbon  steel,  welded  on  to  another 
piece  of  f  dia.,  110  point  carbon  Carnegie  electric  tool  steel 
No.  4.  The  low  carbon  ends  were  drilled  and  threaded  to 
receive  the  stud  of  the  bench  rod,  and  the  high  carbon  ends 
were  upset,  machined,  and  used  as  working  heads.  Six  sam- 
ples of  each  kind  of  steel  were  prepared  and  sent  to  the  Thom- 
son Electric  Welding  Co.  of  Lynn,  Mass.,  to  be  welded. 

After  welding  the  mandrels  were  subjected  to  the  follow- 
ing heat  treatments  and  operations: 

1.  Head-end  annealed  after  upsetting. 

2.  Head-end    machined,    and    hardened    by    quenching    in 

water. 

3.  Mandrels  worked  on  draw  benches  until  worn  out  or 

broken. 

4.  Entire  length  of  mandrels  heated  to  1450°  F.  and  cooled 

in  air. 

5.  Mandrels  subjected  to  tensile  test  to  destruction. 
Mandrel  No.  1.— Pulled  5125  ft.   of  1X-H2  in.  to  JX.107  in., 

17  point  carbon.  Rather  heavy  pull.  Broke  stud  once,  and  used 
again  after  replacing  same.  Pulled  to  destruction  in  standard 
testing  machine,  and  failed  2J  in.  below  weld  on  low  carbon  end, 
at  a  stress  of  59,000  Ib.  per  sq.  in.  Weld  stronger  than  low 
carbon  round. 

Mandrel  No.  2.— Pulled  3360  ft,  of  !3/i6X.46  in.  to  3/4X.38 
in.,  17  point  carbon.  Not  badly  worn  at  end  of  load.  Pulled 
to  destruction  in  testing  machine,  and  failed  1  in.  below  weld 
on  low  carbon  end,  at  a  stress  of  58,800  Ib.  per  sq.  in.  Weld 
stronger  than  round  of  30-40  point  carbon  of  same  cross-section. 

Mandrel  No.  3.— Pulled  2400  ft.  of  1X-H2  in.  to  JX.107 
in.,  17  point  carbon.  Broke  at  stud  and  replaced  by  another 
mandrel.  Pulled  to  destruction  in  testing  machine,  and  failed 
on  weld  at  stress  of  58,000  Ib.  per  sq.  in.  Weld  98%  efficient, 
referred  to  mandrel  No.  1. 

Mandrel  No.  4.— Pulled  2250  feet  of  13/4X.200  in.  to 
lVioX-200  in.,  17  point  carbon.  In  good  shape  at  end  of  load. 


396  ELECTRIC  WELDING 

Pulled  to  destruction  in  testing  machine  and  failed  on  weld, 
at  a  stress  of  56,900  Ib.  per  sq.  in.  Weld  96%  efficient,  referred 
to  mandrel  No.  1. 

Mandrel  No.  5.— Pulled  402  ft.  of  1X.H2  in.  to  JX-108  in., 
17  point  carbon.  Broke  off  at  stud  of  rod,  tube  being  unduly 
oversize.  Pulled  to  destruction  in  testing  machine,  and  failed 
on  weld  at  a  stress  of  53,700  Ib.  per  sq.  in.  Weld  91%  efficient, 
referred  to  mandrel  No.  1. 

Mandrel  No.  6. — Mandrel  broken  at  thread  on  first  tube. 
Tube  over-size.  Mandrel  lost. 

Conclusion. — Out  of  five  mandrels  subjected  to  a  tensile 
test  to  destruction  after  being  worked,  on  the  benches,  two 
show  that  the  weld  is  stronger  than  the  30-40  point  carbon 
round  solid  rod,  and  the  other  four  showed  efficiency  of  91% 
to  98%,  referred  to  59,000  Ib.  per  sq.  in.  The  maximum 
required  efficiency  is  not  over  70%.  Therefore  the  mandrels 
passed  all  requirements  for  strength  and  service. 

Strength  of  High  Carbon  Steel  Welds. — In  order  to  throw 
some  light  upon  the  chemical  and  physical  changes  induced  by 
the  welding  process,  pieces  of  0.97  per  cent  carbon  drill  steel, 
of  |  in.  diameter,  were  studied  after  butt  welding,  writes  E.  E. 
Thum  in  Chemical  and  Metallurgical  Engineering,  Sept.  15, 
1918.  Test  pieces  of  the  original  stock  and  of  both  annealed 
and  unannealed  welds  were  made  by  mounting  in  a  lathe,  re- 
moving the  excess  metal  of  the  fin,  and  then  turning  or  grinding 
a  short  length  of  the  bar  accurately  to  a  diameter  of  J  in., 
with  the  weld  in  the  center  of  the  turned  portion.  In  the 
unannealed  welds,  the  turned  portion  was  but  J  in.  in  length 
in  order  that  the  failure  would  be  forced  to  occur  within  the 
portion  of  the  bar  altered  in  constitution  by  the  welding  heat. 
Tension  tests  of  the  unannealed  welds  showed,  in  all  cases,  a 
failure  with  little  or  no  necking  occurring  at  the  end  of  the 
turned  portion — that  is  to  say,  farthest  from  the  weld  and  in 
the  softest  portion  of  the  test  piece.  The  strength  this  de- 
veloped was  much  higher  than  even  the  strength  of  the  original 
steel,  and  it  is  clearly  evident  that  all  parts  of  this  weld  have 
a  higher  ultimate  strength  than  the  original  bar.  The  average 
results  of  the  tension  tests  follow: 


MAKING   PROPER  RATES   FOR  ELECTRIC   WELDING     397 

Ultimate  Contraction  Elongation 

Strength  Lb.  in  Area?        in  £  In. 

per  Sq.  In.  Per  Cent       Per  cent 

Original  tool  steel 114,100  12                 10 

Unannealed  weld 158,700  2                   3 

Weld  annealed  at  750°  C.  (1382°  P.)..   100,800  24                16 

In  the  annealed  bars  failure  always  occurred  at  the  weld, 
accompanied  by  considerable  necking,  strictly  limited  to  the 
close  proximity  of  the  point  of  failure. 

The  results  of  a  series  of  tests  on  butt-  and  spot-welds  made 
by  G.  A.  Hughes,  electrical  engineer  of  the  Truscon  Steel  Com- 
pany, Youngstown,  Ohio,  were  reported  as  follows: 

TESTS  MADE  ON  BARS  OF  SOFT  STEEL,  1  IN.  SQ.,  BUTT-WELDED  AND 

MACHINED  TO  THE  SIZE  OF  THE  BAR. 

Test  No.             Volts                 Amps.  Kw.  Power  Factor 

1  220         220  40.  91 

2  220         220  40.  91 

3  220         210  39.  84 

4  218         210  39.5  86 

5  220         210  39.  84 

All  tension  tests  were  pulled  at  a  speed  of  y2  in.  per  min. 
Nos.  1,  2  and  3  were  pulled,  while  Nos.  4  and  5,  were  sheared. 
On  the  different  tests,  No.  1  failed  in  the  weld  at  48,800  lb.; 
No.  2  failed  in  the  weld  at  52,300  lb. ;  No.  3  failed  back  of  the 
weld  at  50,100  lb. ;  No.  4  failed  at  51,500  lb.  and  No.  5  at 
50,300  lb. 

These  tests  indicate  that  the  ultimate  shearing  strength  of 
such  a  weld  closely  approaches  the  ultimate  tensile  strength. 

Pieces  of  soft  steel,  3/16  in.  thick  and  5  in.  wide,  with  an 
ultimate  tensile  strength  of  56,150  lb.,  were  butt-welded  and 
pulled  with  the  following  results: 

Test  No.  Manner  of  Failure  Lb.  .  Per  Cent 

1  %  in  plate  and  %  in  weld  51,000  91 

2  In  plate  just  back  of  weld  52,000  93 

3  "      "  "  "  "  "  53,400  95 

4  "      "  "  "  "  "  52,000  93 

5  "      "  "  «  «  «  46,100  82 

6  ft  .it  i<  tt  ii  n  51,900  93 

On  six  samples  of  spot-welded  single  lap-joint  sheets  of  14 
gage  steel,  3  in.  wide,  welded  with  a  5/i«  in-  sPot'  the  average 
at  which  the  welds  pulled  out,  was  4480  lb. 


398  ELECTRIC  WELDING 

The  ultimate  tensile  strength  of  a  piece  of  plate  of  14  gage, 
was  64,500  per  sq.  in.  The  ultimate  shearing  load  per  weld 
(two  spots  with  an  area  of  0.0742  sq.  in.  each)  averaged  8942 
Ib.  Approximate  total  welded  area,  0.1484  sq.  in.  This  gives 
an  ultimate  shearing  strength  for  1  sq.  in.  of  weld,  of  about 
60,200  Ib.  On  steel  %  in.  thick  and  2  in.  wide,  welded  with 
a  spot  having  an  area,  measured  with  a  planimeter,  of  0.476 
sq.  in.,  the  failure  under  pull  was  at  34,650  Ib.  Examination 
of  the  welds  showed  them  to  be  under  both  a  tensile  and  a 
shearing  action.  A  piece  of  the  same  steel  tested  for  ultimate 
strength,  failed  at  eftjSOO  Ib.  per  sq.  in.  This  shows  that  the 
weld  was  stronger  than  the  original  metal. 

The  final  conclusions  drawn  by  Mr.  Hughes  from  his  tests, 
are  that,  in  general,  the  ultimate  tensile  strength  of  a  properly 
made  butt-  or  spot-weld,  is  about  93  per  cent  of  that  of  the 
parent  metal,  and  the  ultimate  shearing  strength  of  a  properly 
made  butt-  or  spot-weld  is  also  about  93  per  cent. 

ELEMENTARY  ELECTRICAL  INFORMATION 

What  is  a  Volt? — This  is  a  term  used  to  represent  the  pres- 
sure of  electrical  energy.  In  steam  we  would  say  a  boiler 
maintains  a  pressure  of  100  pounds.  This  term  relates  to  pres- 
sure only  regardless  of  quantity,  just  as  the  steam  pressure 
of  a  boiler  has  nothing  to  do  with  its  capacity. 

What  is  an  Ampere? — This  term  is  used  to  represent  the 
quantity  of  current.  In  the  case  of  steam  or  water  we  speak 
of  carrying  capacity  of  a  pipe  in  cubic  feet,  while  in  electricity 
the  carrying  capacity  of  a  wire  is  given  in  amperes. 

What  is  a  Watt? — This  is  the  electrical  unit  of  power  and 
equals  volts X amperes.  One  mechanical  horsepower  is  the 
equivalent  of  746  watts. 

What  is  a  Kilowatt  or  kw.? — 1000  watts,  kilo  merely  in- 
dicating 1000.  It  is  the  most  commonly  used  electrical  unit 
of  power  and  one  kilowatt  of  electrical  energy  is  equivalent 
to  one  and  one-third  mechanical  horsepower. 

What  is  a  Kilowatt  Hour  or  kw.-hr.? — This  is  the  electrical 
equivalent  of  mechanical  work,  which  would  be  stated  in  the 
latter  in  terms  of  horsepower  hour.  It  means  the  consumption 
of  1000  watts  of  electrical  energy  steadily  for  one  hour  or  any 
equivalent  thereof  (such  as  5000  watts  for  12  minutes)  and 


MAKING  PROPER  RATES  FOR  ELECTRIC  WELDING     399 

is  the  unit  employed  by  all  power  companies  in  selling  electric 
power,  their  charges  being  based  on  a  certain  rate  per  kw.-hr. 
consumed. 

What  is  kva.? — This  means  Kilo  volt  amperes  or  volts  X 
amperes-f-1000.  This  term  is  used  only  in  alternating  current 
practice  and  is  used  to  represent  the  apparent  load  on  a 
generator.  In  any  inductive  apparatus,  such  as  a  motor  or 
welder,  a  counter  current  is  set  up  within  the  apparatus  itself, 
which  is  opposite  in  direction  to  and  always  opposes  the  main 
current  entering  the  apparatus.  This  makes  it  necessary  for 
the  generator  to  produce  not  only  amperes  enough  to  operate 
the  motor  or  welder  but  also  enough  in  addition  to  overcome 
this  opposing  current  in  either  of  the  latter,  although  the  actual 
mechanical  power  required  to  run  the  generator  is  only  that 
to  supply  watts  or  electrical  energy  ( volts X amperes)  actually 
consumed  in  the  motor  or  welder.  Hence,  the  kw.  demand 
of  a  welder  represents  the  actual  useful  power  consumed,  for 
which  you  pay,  while  the  kva.  emand  represents  the 
vo Its X total  number  of  amperes  impressed  on  the  welder-f-1000, 
to  also  overcome  the  induced  current  set  up  within,  but  it  is 
the  kva.  demand  that  governs  the  size  of  wire  to  be  used  in 
connecting  up  the  welder.  Kw.  divided  by  kva.  of  any 
machine,  represents  the  power  factor  of  that  machine,  which 
is  usually  expressed  in  per  cent. 


INDEX 


Adapters  for  using  carbons  in  metal- 
lic electrode  holder,  *67 
Adjustable    table    for    spot   welding 

machines,  *288,  *292 
Adjustment  of  die  points  for  spot- 
welding,  *284,  *297 
All- welded  mill  building  details,  *166 
Alternating-current    apparatus,    *42, 
*43,  *44 

arc  welding,  85 

Aluminum  butt-weld,  *249,  252 

— •  welded  to  copper  by  percussion, 

*274 

American  Institute  of  Electrical  En- 
gineers, paper  read  be- 
fore, by  H.  M.  Hobart, 
167 

Mining  and  Metallurgical 

Engineers,     paper    read 
before  the,  223 
American  Machinist,  47,  66,  134,  324, 

339 

American    Boiling    Mills    Co.,    elec- 
trodes made  by,  13 

—  Steel    and    Wire    Co.,    electrodes 

made  by,  13 

gage     numbers     of, 

140 

—  Welding  Society,  214 

Ammeter  charts  of  operation  of  Mor- 
ton automatic  metallic-electrode 
welding  machine,  *224 

Amount  of  metal  deposited  per  hour 

in  arc  welding,  89 
Ampere,  what  is  a,  398 
Andrews,  H.  H.,  212 

—  W.  S.,  23 


Angle  and  plate  construction,  *94 

—  for  holding  carbon  electrode,  69, 

*70 

—  of  electrode  in  machine  welding, 

229 

scarf  for  arc  welding,  60 

Annealing  butt  welds,  245,  *246 

—  welded  tools,  356 

Apparatus  used  in  Bureau  of  Stand- 
ards arc  welding  work,  *174 

Appearance  of  tension  specimen  af- 
ter test,  *183 

Application  of  carbon  arc  welding, 
77 

' '  Application  of  Electric  Welding 
to  Ship  Construction, "  paper  by 
Jasper  Cox  on,  168 

Arc  and  fusion  characteristics,  52 

— ,  carbon,  characteristics  of,  *70 

—  control,  51 
exercise,  *52 

on  Morton  machine,  225 

—  formation,  50 

—  -fused  metal,  formation  of  blocks 

of,  *175,  176 

—  — ,  macrostructure  of,  184,  *185, 

*186,  *187 

,  tests  of,  by  Bureau  of  Stand- 
ards, 189 
,  — ,  by  Wirt-Jones,  189 

—  steel,  change  in  nitrogen  of,  upon 

heating,  209 

,  metallography  of,   191 

— ,  microstructure  of,   192,   *193, 

*194,     *196,     *198,      *199, 

*200,      *202,      *204,      *206, 

*207,      *208 
,  physical  properties  of,  171 

401 


402 


INDEX 


Arc  steel,  summary  of  results  of  the 
study  of  the  metallography 
of,  212 

— -  length  for  carbon-electrode  work, 
71 

for  various  currents  when 

using  carbon-electrodes,  71 

—  —  in  metallic-electrode  welding, 

82 

—  maintenance,  50 

—  manipulation,  49 

in    carbon-electrode    welding, 

69 

— ,  polarity  of,  in  welding,  53 
— ,  short  and  long,  deposits,  *55 
— , welding,  *54 

—  stability,  54 

—  weld  inspections,  63,  96,   103 

—  welding,    automatic,    214,    *217, 

*218,  *230,  *236 

circuits  as  first  used,  *3 

equipment,  9 

-  high-speed  tool  tips,  162,  *164 

—  jobs,  examples  of,  127,  *130, 

*133,  *137,  *138,  *139, 
*140,  *141,  *142,  *146, 
*147,  *148,  *149,  *153, 
*154,  *155,  *156,  *157, 
*158,  159,  160,  161,  163, 
164,  166 

—  machine,     a     semi-automatic, 

223,  *230 
Arc  Welding  Machine  Co.,  The,  40 

Co.  's    constan  t-current 

closed  circuit  system, 
40 
—  —  electrode    holder,    *16, 

*17 
procedure,  81 

-  set,  the  G.  E.,  *28 
,  speed  of,  167 

, ,  by   machine,   220,   221, 

222,  233,  238 

terms  and  symbols,  109 

Arcwell  Corporation,  43 

—  outfit  for  a-c  current,   *43 
Armature  shaft  built  up,  *153 


Arsem  furnace,  208 

Automatic    arc   welding,    214,    *217, 

*218,  *230,  *236 

Automatic  Arc  Welding  Co.,  223 
Automatic    arc-welding    head,    215, 

*217,  *218 
machine,    work    done    by, 

219 

—  butt-welding      machines,       *244, 

*245 

—  chain  making  machine,  *269 

-  hog-ring  mash  welding  machine, 

*305,  *306 

Automatic  Machine  Co.,  268 
Automatic   Pulley  spot-welding  ma- 
chine, *301 

—  spot-welder  for  channels,  *300 
Automobile    body    spot-welding    ma- 
chine    with     suspended     head, 
*294 

—  muffler  tubes,  seam  welded,  *372 

—  rim  butt-welding  work,  252,  *255, 

*259 

Axle  housings  repaired,  *156 
— ,  worn,  built  up,  *160 


B 

Back-step  arc  welding,  84 
Balancer-type  arc  welding  set,  *28 
Band  saw  welding,  *251,  252 
Bench  type  of  spot-welding  machine, 

*248 

Bernardos  process,  the,  1,  2,  *3 
Blow-pipe,  electric,  the,  1,  *2 
Body,  automobile,   spot-welding  ma- 
chine with   suspended   head,    *294 
Boiler  tube  arc  welding,   *142,   143 

rolling   machine,    simplest 

form  of,  *331 

welding  with  the  arc,  *89 

—  tubes,  leaks  in,  333 

,  ready  for  flash-welding,   *.",L)9 

Bolt  holes,  filling,  160 
Booth,  the  welding,  48 
Bouchayer's  spot-welding  apparatus, 

*6,  7 
Box,  spot-welding  a  sheet  steel,  *283 


INDEX 


403 


Brass,  butt-welding,  267 

—  seam  welding,  366 

Bronze,    welding    with    carbon    arc, 

76 

Bucket  voiding  jig,  *375 
Building  up  a  surface  with  carbon 
arc,  *72 

round  work,  speed  of,  223 

worn  shafts  and  axles,  *153, 

*160 
Built-up    carbon    arc    weld,    section 

through  a,  *73,  *75 
Bureau  of  Standards,  study  of  arc- 
fused  steel  at,  171 

,  tests  on  arc-fused  steel  at, 

191 

Burning,  lead,  outfit,  *45,  46 
Butt  weld    (arc),  definition  of,   110 

,  boiler  tube  ends  prepared  for, 

*327 

—  -welding     attachment     for     spot- 

welding  machine,  *286 

—  boiler  tubes,  336 

—  device,  first  practical,  *4 

—  end  rings,  *266 

—  jobs,    examples    of,    247,     *249, 

*250,    *251,    *255,    *265,    *266, 
*267,  *268 

—  machine,  principal  parts  of,  *240 
work     clamps,      *242,      *243, 

*257 

—  machines,  *345,  *347,  *348,  *351 
and    work,    239,    *240,    *241, 

*244,  *245,  *246,  *251, 
*254,  *256,  *257,  *259, 
*261,  *262,  *263,  *264, 
*267,  *268 

—  patents,  4 

— •  pipe,    cost    and   consumption    of, 
258 

—  rod  up  to   %  in.   dia.,  cost  and 

current  consumption  of,  248 

—  stock  up  to  2   in.  dia.,  cost  and 

current  consumption  of,  263 

—  -welds,    metallic    electrode,    data 

on,  32 
— ,  strength  of  resistance,  394 


Cable,  size  of,  for  arc  welding  work, 

18 

Cain,  J.  R.,  177,  178 
Cam-operated  butt-welding  machine, 

*244,  *245 

Can  seams,  line-welding,  *308 
— •  welding  jig,  *374 
Car  axle  enlarged,  *160 

—  equipment,   electric,   maintenance 

of,  150 
Carbon  arc,  characteristics  of,  *70 

,  cuts,  examples  of,  *77 

spot-welding,  *5,  *7 

•  welding,  *15 

,  application  of,  77 

,  filler  used  for,  68 

—  electrode  apparatus,  original,  *3 
arc      seam-welding     machine, 

*236,  237 

welding  and  cutting,  66 

current  used  with,  66,  68,  71, 

74,  78,  80 

cutting   speeds,   31 

process,  10 

,  size  of,   10,  68 

Cases,  motor,  reclaimed,  *154 
Cast  iron,  rate  of  cutting,  with  car- 
bon arc,  79 

,  welds,  strength  of,  131 

Caulking  weld    (arc),   definition   of, 

116 

Chain  machine,  automatic,  *269 
Challenge  Machinery  Co.,  288 
Change    in    nitrogen    content    upon 

heating  arc-fused  steel,  209 
Channel   iron   spot-welding  machine, 

automatic,  *300 

Characteristic  appearance  of  tension 
specimen  after  test,  *183 

—  " needles"  or   "plates"  in  arc 

fused  steel,  195,  *196,  *198, 
*199,  *200,  *202,  *204,  *206, 
*207,  *208 

—  structure     of     electrolytic     iron, 

*199 


404 


INDEX 


Characteristics  of  arc  and  fusion,  52 

carbon  arc,  *70 

the  metallic  arc  weld,  factors 

that  determine  the,  97 

— ,  thermal,  of  arc-fused  iron,  210, 
*211 

Chemical  analyses  of  arc  deposited 
specimens,  105 

Chemical  and  Metallurgical  Engi- 
neering, 171,  396 

Chemical  composition  of  metallic 
electrodes,  effects  of  the,  104 

Chicago,  Rock  Island  and  Pacific 
railroad  arc  welding  work,  84 

Chubb,  L.  W.,  269 

Circuit,  schematic  welding,  *10 

Circular  arc  welding,  automatic, 
*217 

Clamp   for   butt-welding  pipe,    *257 

heavy,  flat,  butt-welding 

work,  *243 

tool  welding,  *346 

— ,  foot-operated,  for  butt-welding 
work,  *242 

— ,  hand-operated,  for  butt -welding 
work,  *242 

—  toggle     lever,     for     butt-welding 

round  stock,  *242 

Clamping  distance,  effect  of,  on 
time  and  energy  demand,  385 

—  jaws  for  boiler  tube  work,  *337 
Clamps  for  work  in  butt-welding  ma- 
chines, *242,  *243,  *257 

Classes  of  electric  welding,  1 
Close-up     of    tool-welding    machine 
with  work  in  place,  *352 

—  view    of    left-hand    tool-welding 

clamp,  *346 

Coating  for  metal  electrodes,  176 

Coils,  butt-welding  pipe,  *256 

Collins,  E.  F.,  263 

Combination  arc  welding  symbols, 
118,  *119,  *120,  *121,  *122, 
*123,  *124,  *125,  *126 

—  spot-  and  line-welding  machines, 

307,  *308,  *309,  *310 

e  wpld  (arc),  definition  of, 


Composition  of  electrodes  before 
and  after  fusion,  177, 
178 

used    in    Morton   machine, 

227,  228,  229 

metallic  electrodes,  12 

Welding       Committee       elec- 
trodes, 107 

Comstock,  G.  F.,  reference  to,  197 
Concave   weld    (arc),    definition   of, 

118 

Condenser,  arc  welded,  *138 
Connections   for   G.    E.    constant-en- 
ergy, constant-arc  set,  *30 
Constant-current  closed-circuit  weld- 
ing outfit,  40 

Contraction    of    deposited    metal    in 
arc  welding,  58,  *59 

—  and  expansion  of  parent  metal  in 

arc  welding,  57,  *59 
Control  of  arc  direction  exercise,  *52 
travel,  51 

—  panel  for  balancer  set,  *29,  *30 
Controlling  the  arc  on  Morton  ma- 
chine, 225 

Convenient  setting  of  machine  for 
spot-welding  sheet  metal  work, 
*295 

Copper  butt-welding,  263 

-welds,  *249,  252 

—  jaws  for  boiler  tube  work,  *337 
holding    large    heads    and 

small  shanks,  *350 

welding    various    sizes    of 

tools,  *349 

—  welded   to   aluminum   by  percus- 

sion, *274 

— ,  welding,  with  carbon  arc,  76 
Correct  welding  posture,  *49 
Cost   of  arc   welding,   90 

in  railroad  work,  144 

butt-  and  mash-welding,  vari- 
ous sizes,  362 

butt-welding   work,   248,   258, 

263 

machine  and  hand  arc-welding 

compared,  221,  222 
metallic  electrode  welding,  32 


INDEX 


405 


Cost  of  percussive  welds,  272 

pod  welds,    147 

repairs  in  welding  flues,  336 

seam   welding,   378 

spot-welds,  321 

-:—  — •  welding  boiler   tubes,  335 
Cox,  H.  Jasper,  168 
Crane  wheels,  repaired,  *221 
Crank  forging  weld,  *250,  252 
Crankshaft,    arc    welding    a    6-ton, 

*161,  162,  *163 
Cross-current    spot-welding   machine, 

*302,  *303 
Cross-overs,       repaired       manganese 

steel,  *147 

Current    action    in    a    Taylor    spot- 
welding  machine,  *304 

—  and   electrode   diameter,   relation 

of,  *13,  14 

—  consumption  for  butt-  and  mash- 

welding     various     sizes, 

362 
butt-welding,      248,      258, 

263 

welding  6-in.  seam,  378 

in  carbon  arc  cutting,  80 

—  density  of  electrode,  61 

—  for  ,  given   cases  of  arc  welding, 

169 

—  required    for    metallic    electrode 

welding,  32 

percussive  welds,  *273 

ship     plate     spot-welding, 

311,   315,  317,  318,   319 
spot-welds,  321 

—  used  for  automatic  arc  welding, 

220,  221,  222,  223,  228, 
232,  238, 

cutting  with  the  carbon 

arc,  78,  80 

various  sizes  of  carbon- 
electrodes,  68 

in  Bureau  of  Standards  tests, 

176 

— butt-welding,  240,  243, 

247,  248,  255,  258,  259, 
260,  261,  262,  263 


Current    used    for   carbon    electrode 

process,  11 
metallic  electrode  process, 

11 

—  values    for    plates    of    different 

thickness,  14 

—  variation,  effect  of,  on  strength 

of  arc  weld,  102 
Currie,  H.  A.,  143 
Curves  showing  thermal  characteris- 
tics of  arc-fused  iron,  *211 
Cutting    speeds    with    carbon    elec- 
trodes, 31 

—  with  the  carbon  arc,  77 
,  current  used  in,  78, 

80 

Cutting-off  machine  for  boiler  tubes, 
*325 

Cuts  made  with  the  carbon  arc,  ex- 
amples of,  *77 

Cylinder,  locomotive,  welding  with 
the  arc,  144 

Cylinders,  Liberty,  butt-welding 
valve  elbows  on,  *268 


Dangerous  light  rays,  23 

Data  for  metallic  electrode  butt  and 

lap  welds,  32 
De  Beriardo  spot-welding  apparatus, 

the,  *5,  7 
Decimal  equivalents  of  an  inch  for 

millimeters,  B.  &  S.  and  Birming- 
ham wire  gages,  323 
Demand,     maximum,     in     resistance 

welding,  387 
de  Meritens,  1 
Deposit  obtained  with  short  and 

long  arc,  *55 

—  per  hour,  arc  welding,  89,  146 
— ,  the&ry  of  electrode,  223 
Deposited  metal,   contraction  of,  in 

arc  welding,  58,  *59 
Deposits    of    short    and    long    arcs, 

*102,  *103 
Design  of  arc  welded  joints,  90 


406 


INDEX 


Details  of  percussive  welding  ma- 
chine and  wiring  diagram, 
*271 

rotor  welding  machine,  *265 

seam  welding  roller  head, 

*368 

standard  spot-welding  ma- 
chines, 278,  *279 

Diagram  of  control  of  feed  motor 
for  automatic  arc-welding 
machine,  *219 

flange  seam  welding  opera- 
tion, *380 

Die-points  for  heavy  spot -welding, 
314 

spot-welding  machines,  288, 

*289,  *290,  *291,  *297, 
*304 

Different  makes  of  arc  welding  sets, 
28 

Direction  of  arc  travel,  51 

Double  bevel,  definition  of,  as  ap- 
plied to  edge  finish,  114 

—  ' '  V, ' '  definition  of,  as  applied  to 
edge  finish,  113 

Drill  blanks  just  welded,  *349 

Drills,   Stellite  tipped,   *348 

Driving  wheel  welding,  *141,  143 

Duplex  spot-welding  machine  with 
6-ft.  throat  depth,  *316 

Dynamotor,  plastic  arc,  welding  set, 
35,  *36 

E 

Edge  finish,  112,  113,  114 

Edges,  flanged,  welded  with  carbon 

arc,  *75,  76 

Effect  of  clamping  distance  on 
time  and  energy  demand, 
385 

pronounced  heating  upon  the 

structure  of  arc-fused  iron, 
*206,  *207,  *208 
Effects  of  the  chemical  composition 

of  metallic  arc  electrodes,  104 
Electric  Arc   Cutting  and   Welding 
Co.,  44 


Electric  arc,  heat  of  the,  9 

—  and  oil  heating   of   boiler   tubes 

compared,  335 

—  "  blow-pipe, "  the,  *2 

—  car  equipment  maintenance,   150 
Electric  Railway  Journal,  150 
Electric    seam    welding,    resistance, 

365 

—  welded  ship,  134 

—  welding,  classes  of,  1 
Electric    Welding    Co.    of    America, 

building  for  the,  164 
Electric  welding  of  high-speed  steel 

and  Stellite  in  tool  manufacture, 

343 

Electrical  inspection  of  welds,  98 
Electrical  World,  382 
Electrically    welded    mill    building, 

164 

Electrode,  angle  of,  in  machine  weld- 
ing, 229 

— ,  carbon,  original  apparatus,  2,  *3 
— ,  — ,  size  of,  68 

—  current  density,  61 

—  deposit,  theory  of,  223 

—  diameter  versus  arc  current,  *13 

—  diameters  for  welding  steel  plate, 

101 

—  holder,  a  simple  form  of,  *16 

—  — ,  special  form,  *16,  *17 

—  material,    analysis    of,    used    in 

Morton  machine,  227,  228,  229 
— ,  metallic,  original  apparatus,  2,  *3 
— ,  — ,  speed  of  welding  with,  32 
— ,  size  of  for  arc   welding,  British 

practise,  169 

—  wire,  best,  to  use  in  arc-welding 

machine,  231 

Electrodes  before  and  after  fusion, 
composition  of,  177,  178 

— ,  composition  of  Welding  Commit- 
tee, 107 

— ,  fusion  of,  50 

— ,  graphite — see  Carbon 

— ,  hardness  of,  180,  181 

— ,  metallic,  composition  of,   12 

— ,  — ,  made  by  various  firms,  13 

— ,  selection  of,  12 


INDEX 


407 


Electrodes,  size  of,  13,  14 
— ,  tensile    properties    of,    179,    180, 
181 

—  used  for  carbon  arc  welding,  66, 

*67,  68 
Electro-percussive  welding,  269 

machine,  *270,  *271,  272 

Elementary    electrical    information, 

398 

End,  strip,  welding  jig,  *376 
Energy    consumption    of    resistance 

welding  for  commercial  grades  of 

sheet  iron,  384 
Escholz,  O.  H.,  47,  66,  96 
Etching  fluid,  55 

—  solution     used     by     Bureau     of 

Standards  for  steel,   185,   186, 

187,    193,    194,    196,    198,    199, 

200,   202,    204,    206,   207,    208 

Equipment,  a  welder 's,  64 

Examples  of  arc  welding  jobs,  127 

*130,      *133,      *137, 

*138,      *139,      *140, 

*141,      *142,      *146, 

*147,      *148,      *149, 

*153,      *154,      *155, 

*156,      *157,      *158, 

*159,      *160,      *161, 

*163,      *164,      *166 

work,    *87,    *88,    *89 

butt-welding  jobs,    247,    *249 

*250,     *251,     *255,     *265, 
*266,     *267,     *268 

—  —  seam     welding,     *371,     *372, 

"374,  *375,  *380 
— •  —  welded  ship  parts,  *137 
Exercises    for    the    beginner   in    arc 

welding,  58,  *59 
expansion  and  contraction  of  parent 

metal  in  arc  welding,  57,  *59 
Eye  protection  in  iron  welding  op- 
erations, 23 


Face   masks   and   shields,    *15,    *18, 

*19 
Factors    that    determine    degree    of 

fusion,  64 


Federal  butt- welding  machines,  261, 

*262,  *263,  *268 
Federal   Machine    and    Welder    Co., 

261,  297 
Federal  spot-welding  machines,  *296, 

297,  *299,  *300,  *301 

—  water-cooled    die    points,     *297, 

*298 
Feed  control  diagram  of  arc  welding 

machine,  *219 
Ferride  Electric  Welding  Wire  Co., 

electrodes  made  by,  13 
Fillet  weld   (arc),  definition  of,  111 
Filler  material  for  carbon  arc  weld- 
ing, 68 

—  rods,  fused  ends  of,  used  in  car- 

bon arc  welding,  *74 
Filling  in  bolt  holes,  160 

—  sequence    in    arc    welding,    *83, 

*84,  *85 

Firebox  sheet  work,  *95 
Flange,  repair  of  electric  car  wheel, 

*157,  *158 

—  seam  welding,  374,  *377,  *380 
,  diagram   of  operation  of, 

*380 

Flanged  edges  welded  with  carbon 
arc,  *75,  76 

—  seam   welding  with   carbon   arc, 

*75,  76 

Flash-welding  boiler  tubes,  336,  338 
Flat  position  defined  as  applied  to 

ship  work,  *114,  115 
Flue   ends   just    beginning   to   heat, 

*340 

almost  hot   enough  for  weld- 
ing, *341 

prepared  for  flash-weld,  *329 

,  rolling    out    upset    metal    on, 

*341 

—  parts  in  machine  ready  for  weld- 

ing, *340 

—  welding  (arc),  *142,  143 
machine,  close-up  of,  showing 

inside  mandrel,  *339 

—  — ,  pressure  required  for,  337 
with  the  arc,  *89 

—  work,  machine  for,  337 


408 


INDEX 


Flues,  cutting  off  boiler,  *325 
— ,  leaks  in  welded,  333 
Flush  weld   (arc),  definition  of,  118 
Flux  for  flue  welding,  using  a,  330 

—  used  for  seam  welding,  366 
Forge,  the  "water-pail,"  1,  3 
Form    of    points    for    spot-welding, 

*289,  *290,  *291,  *297,  *298,  *304 
Formation  of  arc,  50 
Fractures   of   test    specimen    of   arc 

deposited  plates,  *105 
Frame     welding,     locomotive,     *89, 

*139,  *140 

' l  Free  distance, ' '  meaning  of,  63 
reduction  caused  by  contrac- 
tion, *59 
1 1  Freezing ' '  of  electrodes,  meaning 

of,  50,  64 
Fused    ends    of    filler    rods   used    in 

carbon  arc  welding,  *74 
Fusion  and  arc  characteristics,  52 
— ,  factors  that  determine  degree  of, 
64 

—  of  electrodes,  50 

parent  metal  and  four  layers 

of  carbon  arc  deposit,  *75 
— ,  poor  and  good,  from  arc,  *60 


Galvanized  iron,  welding,  277,  *286 
Gear-case   repair,   *155 

—  cases    with    patches    welded    on, 

*159 

— ,  split,  made  solid,  *160 
General    Electric    arc-welding    gen- 
erator     direct     con- 
nected      to       motor, 
*152 
-  set,  *28 

butt-welding       machine       for 

rotor     work,     *264,     *265, 
*266,  *267 

—  Co.,  17,  28,  46,  151,  154,  214, 
237,  307,  308,  319 

—  —  portable     arc-welding     outfit, 

*151 

General  Electric  Review,  21,  23,  263, 
311 


General    Electric    space-block    spot- 
welding  machine,  *307 

—  features  of  microstructure  of  arc- 

fused  steel,  142 
"George    Washington,"    repair    of 

the,  *130 

German  ships,  extent  of  damage  to 
seized,  128 

—  — ,  repaired,   127 
Gibb  Instrument  Co.,  42 

Glass,  qualities  of  various  kinds  of, 
25 

Good  and  bad  arc  welds,  *100 

Graphite  electrodes — see  Carbon 

Groesbeck,  Edward,  171 

Grooved  tool  parts  to  facilitate  weld- 
ing, *364 

Guards,  spot-welding  12  gage  iron, 
*287 


H 

Haas,  Lucien,  290 

Ham,  J.  M.,  21 

Hand  shield,  using  a,  *15 

—  shields  for  arc  welders,  *15,  *19 
Hardness  of  electrodes,  180,  181 
Harmatta  spot-welding  process,  prin- 
ciple of  the,  *7 

Harness  rings,  welding,  *245 
Hartz   type  boiler  tube  rolling  ma- 
chine, *332 

Heat  conductivity  and  capacity  in 
arc  welding,  57 

—  of  the  electric  arc,  9 

—  treatment  of  arc  welds,  103 
Heating     arc-fused     steel     changes 

nitrogen  content,  209 

— ,  effect  of,  on  structure  of  arc- 
fused  iron,  *206,  *207,  *208 

Heavy-duty  spot-welding  machine, 
*283,  *292,  *303,  *312,  *316, 
*318 

—  experimental     spot-welding     ma- 

chine, *318,  319 
Herbert  Mfg.  Co.,  296 
High  carbon  steel  welds,  strength  of, 

396 


INDEX 


409 


High-speed  steel,  welding,  343 

— •  to  low-carbon  steel,  welding,  344 

—  tool  tips,  arc-welding,   162,  *164 
Hobart,  H.  M.,  167,  189,  223,  390 
Hoe     blades,     welding,     to     shanks, 

*284 
Holder,    electrode,    simple    form    of 

*16 
— ,  — ,  special  form  of,  *16,  *17 

—  for  carbon-electrode,  *67 

metallic-electrode,   *67 

— ,  the  electrode,  48 

Holding   stock    of   unequal   size   for 

butt-welding,  *350 
Holes,   filling  bolt,   160 
— ,  strength     of     spot-welded,     392, 

*393 

Horizontal    position    defined    as    ap- 
plied to  ship  work,  *114,  115 
Housing,    repaired    5-ton    roll,    147, 

*148 

— ,  welded  rear  axle,  *222 
Houston  Ice   Co.,   crankshaft  repair 

for,  162 

How  horn  and  welding  points  may 
be  set  for  spot  welding,  *284, 
*297 

—  the  metal   edges   of   a   tank   are 

arc  welded,  237 
Hub,  welded  automobile,   *221 
Hughes,  G.  A.,  397 


Inclusions  in  arc-fused  steel,  "  metal- 
lic-globule," *194,  195 
Insert  tool  welding,  *355,  *357 
Inspection  of  arc  welds,  63,  96,  103 


Jacob,  W.,  263 

Jaws  and  work  arranged  for  a  mash 
weld,  *361 

—  for  boiler  tube  work,  *337 

—  —  holding    two    sizes    of    stock, 

*350 

—  tool  welding,  *346,  *349,  *350, 
*354,  *355,   *356,  *357 


Jessop,  E.  P.,  13] 

Jigs  for  holding  seam  welding  work, 
372,  *373,  *374,  *375,  *376,  *380 
Joints  arc  welded,  design  of,  90 
— ,  stresses  in  arc  welded,  92,  *93 
Jordan,  Louis,  171 


Karcher,  A.  A.,  288 

Kent,  William,  report  on  butt-welds 
by,  394 

Kerosene,  use  of,  in  inspection,  63, 
98 

Kilowatt-hour,  what  is  a,  398 

— ,  what  is  a,  398 

Kind  of  machine  to  use  for  welding 
flues,  337 

King  face  masks,  *15,  *18 

— •  Optical  Co.,  Julius,  18 

Kleinschmidt  spot-welding  appara- 
tus, the,  *5,  7 

Kva.,  what  is,  399 


La  Grange-Hoho  process,  the,  1,  3 
Lap  weld    (arc),   definition  of,   110 
Lamp  shades,  mash-welding,  *285 
Lap  seam  welding  machines,  368 
— •  -welds,    metallic    electrode,    data 

on,  32 

Lathe  tool,  welded  and  finished,  *354 
Layers  of  filling  material  in  carbon 

arc  welding,  *73,  *74,  *75 
Lead-burning  outfit,  G.  E.,  *45,  46 
— ,  welding,    with    carbon    electrode, 

76 

Leaks  in  welded  boiler  tubes,  333 
Lloyd's  Kegister,  135 
Liberty  motor   cylinders,   butt-weld- 
ing valve  elbows  on,  268 
Light    manufacturing    type    of   spot 

welding  machine,  *281 
-  rays,  dangerous,  23 
Lincoln  Electric  Co.,  21,  37,  81 
—  welding  set,  the,   36,  *37 
Line-welding  can  seams,  *308 
Lining  up  large  crankshaft  for  arc 
welding,  *163 


410 


INDEX 


Load  factor  in   resistance  welding, 
386 

—  tests  of  all-welded  mill  building, 

165 

' '  Locked-in ' '  stresses,  result  of,  62 
Locomotive  arc  welding  work,  140 

—  frame  welding,  *89,  *139,  *140 
Long  and  short  arc  deposits,  *55 
welding  arc,  *54 

Lorain  machine  for  spot-welding 
electric  rail  bonds,  *320,  321 

Lorain  Steel  Co.,  321 

Lunkenheimer  laboratory  tests  of 
spot  welds,  391 

M 

MacBean,  T.  Leonard,   164 
Machine    for    flange-seam    welding, 

.       377 
— ,  kind  of,  to  use  for  flue  welding, 

337 

Machines  for  resistance  butt  weld- 
ing, 239,   *240,   *241,   *244,  *245, 
*246,  *251,  *254,  *256,  *257,  *259, 
*261,  *262,  *263,  *264,  *267,  *268 
Macrostructure   of   arc-fused   metal, 

184,  *185,  *186,  *187 
Maintenance  of  arc,  50 

electric  car  equipment,  150 

Making  a  "mash"  insert  weld,  *359 
— •  proper  power  rates,  382 
Mandrels  used  in  flue  welding,  330, 

331,  333,  *334,  *339 
Manganese     steel     cross-overs,     re- 
paired, 147 
Manipulation  of  arc,  49 

the  arc  in  metallic  electrode 

welding,  82 
Martensite    structure    in    arc-fused 

steel,  *204 
Mash  welding,  284,  *285,  306,  *319 

machines,  *358,  *359,  *360 

Mask,  using  a,  in  arc  welding,  *15 
Masks,  King,  for  arc  welding,  *15, 

•18 

Maximum  demand  in  resistance 
welding,  387 


Mechanical  properties  of  arc-fused 
metal  deposited  at  right 
angles  to  length  of 
specimen,  184 

twelve  good  arc  welds,  173 

twelve  inferior  arc  welds, 

173 

Melting  steel  in  nitrogen  under 
pressure,  212 

Merica,  P.  D.,  197 

Merits  of  electric  and  oil  heating  of 
boiler  tubes,  335 

Metallic  arc  welding,  *15 

—  electrode  apparatus,   original,  2, 

*3 

process,  10,  11 

speed  of  welding  with,  32 

' '  Metallic-globule ' '  inclusions  in 
arc-fused  steel,  *194,  195 

Metallography  of  arc-fused  steel, 
191 

Metals,  non-ferrous,  welding  with 
carbon  arc,  76 

Methods  of  welding  boiler  tubes,  the 
three,  328 

— ,  the  three,  of  welding  boiler  tubes 
compared,  336 

Microphotographs  of  specimens  of 
arc  deposited  metal,  *106 

Microscopic  evidence  of  unsound- 
ness  of  arc-fused  metal,  193 

Microstructure  of  arc-fused  steel, 
192,  *193,  *194,  *196,  *198,  *199, 
*200,  *202,  *204,  *207,  *208 

Mill  building,  electrically  welded, 
164 

,  welded  parts  of,  *166 

Miller,  S.  W.,  197,  201 

Morton,  Harry  D.,  223 

—  semi-automatic    metallic-electrode 

arc-welding  machine,  *230 
Motor  cases  reclaimed,  *154 
Muffler  tube  welding  jig,  *373 

—  tubes,  seam  welded,  *372 

N 

"  Needles "  in  arc-fused  metal,  195, 
*196,  *198 


INDEX 


411 


New  York  Central  railroad  arc  weld- 
ing work,  143 

Nitrates  probably  cause  of  plates  in 
fusion  welds,  197 

Nitride    plates,    persistence    of,    208 

,  two  types  of,  *199 

Nitrogen  content  and  current  den- 
sity, relation  of,  178,  179 

Non-ferrous  metals,  welding,  with 
carbon  arc,  76 


Oesterreicher,   S.   I.,  382 
Oil    and    electric    heating    of   boiler 
tubes  compared,  335 

—  stove    burner    tubes    before    and 

after  seam  welding,  *371 
Oscillograph     chart     of     percussive 
welds  on  18  gage  aluminum  wire, 
273 

Orton,  J.  S.,  104 
Outfit,   selecting   a  welding,   21 
Outfits,  welding,  types  of,  21 
Overhead  position  defined  as  applied 
to  ship  work,  *114,   115 

—  seam  welding,  62 

Overlap     and     penetration     studies, 

*56,  57 
"Overlap,"  meaning  of,  63 


Page  Woven  Wire  Co.,  electrodes 
made  by,  13 

Panel  control  for  balancer  set,  *29, 
*30 

Parent  metal  in  arc  welding,  ex- 
pansion and  contraction  of,  57, 
*59 

' '  Parent  metal, ' '  meaning  of,  63 

Payne,  O.  A.,  168 

Pearlite  islands  in  arc-fused  steel, 
*198 

Pedestal  jaw,  built-up,  *139 

Penetration  and  overlap  studies,  *54, 
57 

— ,  current   required    for   proper,    57 

"  Penetration, "  meaning  of,  63 


Pennington,  H.  E.,  84 
Percussive  welding,  269 

,  the  possibilities  of,  274 

Physical    characteristics    of    plates 
tested,  104 

—  properties  of  arc-fused  steel,  171 
Piloted  cup,  machine  welded,  *227, 

*228,  *229 
Pinion  blank  weld,  *250,  252 

—  pod,  finished  welded,  *148 
Pipe,  cost  and  current  consumption 

for  butt-welding,  258 

—  heading,  *95 

— ,  spot     welding     galvanized    iron, 
*286 

—  welding,  255 

Plastic  arc  dynamotor  set,  35,  *36 

welding  sets,   *33,   *36 

Plate  and  angle  construction,  *94 

—  thickness  versus  arc  current,  *13 
"Plates"    in   arc-fused   metal,    195, 

*196,  *198 
Plates,  nitride,  two  types  of,  *199 

—  probably  due  to  nitrates,  197 

—  remain   long   after   annealing   of 

arc-fused  metal,  208 
Plug  weld    (arc),  definition  of,   111 
Plugged    plates,    strength    of,    392, 

*393 
"  Pocohontas, "   repair   of  the,   132, 

*133 

Pods,  building  up  roll,  *147,  *148 
Points   for   spot-welding   work,   288, 

*289,  *290,  *291,  *297,  *298,  *304 
Polarity  for  carbon  arc  work,  70 

—  in  arc  welding,  53 

carbon  electrode  process,  11 

Portable  arc  welding  set,   *37,  *38, 

*39,  *42,  *43,  *44>  *45 
— •  butt-welding  machines,  247,  *257 

—  spot-welding      machines,       *292, 

*293 

machine    with     27-in.     throat 

depth,  *312 
Position,    correct,    for   using   carbon 

arc  and  filler  rod,  *69 
Positions  of  the  universal  spot-weld- 
ing points,  a  few,  *297 


412 


INDEX 


Posture     and     equipment     of     arc 

welder,  *49 
Potts  Co.,  John,  electrodes  made  by, 

13 

Power  factor  in  resistance  welding, 
383 

—  rates,  making  proper,  382 

—  required     for    percussive    welds, 

272,  *273 

Pressure  required  for  flue  welding, 
337 

heavy    spot   welding,    312, 

313,  317 
Principal    parts    of    a    butt-welding 

machine,  *240 

Projection  allowed  in  welding  boiler 
tubes,  330,  *337,  *340 

—  method  of  welding,  *291 
Properties,     mechanical,     of     twelve 

good  arc  welds,   173 
— , — , inferior  arc  welds,  173 

—  of  arc-fused  metal  deposited  at 

right  angles  to  length  of  speci- 
men, 184 

— ,  tensile,  of  electrodes,  179,  180 
Protecting  the  eyes  in  arc  welding, 

23 

Pulley   spot-welding   machine,   auto- 
matic, *301 

Pulleys    repaired    by    arc    welding, 
*149,  150 


Qualities  of  various  kinds  of  glass, 

25 
Quasi  arc  welding,  86 

— ,  speed  of,  168 
Quasi  Are  Weltrode  Co.,  86 
weltrodes,  how  to  use,  86 


Rail  bonds,  spot-welding,  *320,  321 
—  ends,  built  up  cupped,  146 
Railroad  arc  welding  work,   145 
Railway  Age,  143 
Rate  of  arc  weldipg,  146 


Rates,  making  proper  power,  382 

Rays,  the  infra-red,  23 

— , —  ultra-violet,  23 

— , —  visible  light,  23 

Reamer,  steps  in  making  a  large, 
*353 

* '  Recession, ' '  meaning  of,  63 

' '  Re-entrant  angle, ' '  meaning  of,  63 

Reinforced  weld  (arc),  definition  of, 
117 

Relation  of  arc  current  and  electrode 
diameter,  *13,  14 

microstructure  to  the  path  of 

rupture  in  arc  fused  metal, 
201 

nitrogen  content  and  current 

density,  178,  179 

Removing  broken  taps,  150 

Repairing  crane  wheels,  221 

Resistance  welding,  4 

,  energy  consumption  of,  384 

•  machine,  239 

Rims,  automobile,  butt-welding,  252, 
*255,  *259 

Ring  welded  to  core  with  arc  weld- 
ing machine,  *232 

Rivets  in  a  ship,  number  of,  136 

Rods,  strength  of  mash- welded,  *394 

Roebling's  Sons  Co.,  John  A.,  elec- 
trodes made  by,  13 

Roll  housing,  repaired,  *148 

Rolling  boiler  tubes,  *331,  *332, 
*334,  *341 

—  out  upset  metal  on  flue  ends, 
*341 

Rotatable  head  two-spot  welding 
machine,  298,  *299 

Rotor  ring  butt-welding  work,  263 

Rovvdon,  Henry  S.,  171 

Ruder,  W.  S.,  reference  to,  199,  205, 
208,  209 

Rules,  general,  for  arc  welders,  146 

S 

Saw,  butt-welding  a  band,  *251,  252 
Scarf  angle  for  arc  welding,  60 
"Scarf, "  meaning  of,  63 


INDEX 


413 


Scarf-weld,    boiler    tube    ends    pre- 
pared for,  *326 

welding  boiler  tubes,  336 

Scarfing  machine,  a,  *326 
Scarfs,  typical  arc  weld,  *99 
Schematic  welding  circuit,  *10 
Screens  for  arc  welding,  *19 
Seam,    automatic    arc    welded   tank, 

*222 

— ,  flange,  welding,  374,  *377,  *380 
— ,  flanged,  welding  with  carbon  arc, 
*75,  76 

—  welding  by  the  resistance  process, 

365 

,  current  consumption  for,  378 

,  details    of    roller    head    for, 

*368 

machines,    *367,    *369,    *370, 

*373,      *374,     *375,      *376, 
*377 

,  material  to  use  for,  365,  366 

,  speed  of,  with  automatic  arc 

machine,  222 
Sectional  view  of  carbon  arc  built-up 

weld,  *73,  *75 

Selecting  a  welding  outfit,  21 
Self-contained  portable  welding  set, 

Lincoln,  *37 
Semi-automatic  arc-welding  machine, 

223,  *230 

Shaft,  building  up  a,  with  an  auto- 
matic arc  welding  machine,  *218 
— ,  built  up  motor,  *220 
Shafts,    worn    armature,    built    up, 

*153 

Shearing  strength  of  butt-  and  spot- 
welds,  397 
Sheet  iron  and  steel,  thickness  and 

weight  of,  322 

,  energy   consumption   in  weld- 
ing, 384 

—  metal  arc-welding  machine,  *236, 

237 

work,    convenient    set-up    for 

spot-welding,  *295 

—  steel  box,  spot-welding  a,  *283 
Shell,   cup   for,  welded   by  machine, 

*227,   *228,   *229 


Shells,   motor,   repaired,   *154,   *156 
Shields,  hand,  for  arc  welders,  *15, 

*19 

Ship    parts,    welded,    examples    of, 
*137 

—  plates    automatically    arc-welded, 

*234,  *235 

—  work,  spot-welding  machines  for, 

311,  *312,  *316,  *318,  *319 
Ships,  German,  names  of,  127 
Shops  of  the  Santa  Fe  E.  K.,  339 
Short  and  long  arc  deposits,  *55 

—  welding  arc,  *54 

Single    bevel,    definition    of,    as    ap- 
plied to  edge  finish,  114 

—  "V,"    definition    of,    as   applied 

to  edge  finish,  112 
Size  of  cable  for  arc  welding  work, 
18 

—  —  carbon-electrode,  68 

— •  —  electrode     for     metallic     arc 
welding  of  steel  plate,  101 

electrodes,  13,  14 

Sizes  of  die-points  for  spot-welding, 
*290 

electrodes   used   in   automatic 

arc-welding   machines,    220, 
221,  222,  223,  232,  238 

wire  to  use  for  connecting  up 

different  sizes  of  butt-weld- 
ing machines,  363 
Slavianoff  process,  the,  1,  2 
Sliding   horn   spot-welding   machine, 

*291 

Slip-bands,  188,  202 
Smith,  J.  O.,  134 
Society  of  Naval  Architects,  168 
Solutions,    etching,    for    steel,    185, 
186,  187,   193,  194,  196,  198,  199, 
200,  202,  204,  206,  208 
Space-block     spot-welding     machine, 

*307 

Stability  of  arc,  54 
Special  set  up  of  arc  welding  ma- 
chine for  building  up  a 
shaft,  *218 

machine    for    circular    arc 

welding,  *217 


414 


INDEX 


Speed  of  arc  travel,  51 

welding,  90,   167 

automatic  arc  welding  ma- 
chine, 220,  221,  222,  233, 
238 

building  up  shafts  or  wheels 

with  automatic  arc  ma- 
chine, 223 

cutting  with  the  carbon  arc, 

78,  79,  80 

< carbon  electrode,  31 

deposit  per  hour  in  arc  weld- 
ing, 89 

percussive  welding,  272,  *273 

Quasi- Arc  welding,   168 

seam  welding  with  auto- 
matic arc  machine,  222 

spot-welding,  321 

welding  boiler  tubes,  333,  335 

with  metallic  electrode,  32 

Split-gear  made  solid,  *160 
Spokane  &  Inland  Empire  K.  R.,  re- 
claimed wheels  on,  157 
Spot-     and     line-welding     machines, 
combination,  *308,  *309,  *310 

welded   holes,    strength   of,   392, 

*393 

—  material  that  can  be,  277 
Spot-welding   apparatus,  first  forms 

of,  *5,  *6,  *7,  *8 

—  machines    and    work,    276,    *278, 

*279,  *281,  *282,  *283, 
*284,  *285,  *286,  *287, 
*288,  *291,  *292,  *293, 
*294,  *295,  *296,  *299, 
*300,  *301,  *302,  *303, 
*305,  *307,  *308,  *309, 
*310,  *312,  *316,  *318, 
*319,  *320 

,  details  of  standard,  278 

for     ship     work,     311,     *312, 

*316,  *318,  *319 


—  patents,  *5,  *6, 


*8 


—  power  and  cost  data,  321 

—  tests  on  hoop  iron,  *390,  391 
Spraragen,  William,  167 

Square   patch    arc    welding   method, 

*85 


Stalls,  individual,  for  arc  welders, 
*20 

Steel  etching  solutions,  185,  186, 
187,  193,  194,  196,  198,  199, 
200,  202,  204,  206,  207,  208 

— ,  melting,  in  nitrogen  under  pres- 
sure, 212 

—  plates,  rate  of  cutting,  with  the 

carbon  arc,  80 

—  seam  welding,  366 

—  wire  butt-weld,  *250,  252 
Stellite  insert  welding  jaws,  *357 
— ,  jaws  used  for  welding,   *356 

—  -tipped  roughing  drills,  *348 
— ,  welding,  343 

Steps    in    the    making    of    a    large 

reamer,  *353 

Stove  parts,  spot-welding,  using 
swinging  bracket  support,  *288 

—  pipe  dampers,  spot  welding,  *285 
Straight,  definition  of,  as  applied  to 

edge  finish,  113 
Strap    weld    (arc),    definition   of   a, 

110 
Stratton,  Director  of  the  Bureau  of 

Standards,  171 
Strength  of  arc  deposited  plates,  104 

weld,    variation    of,    with 

change    of    arc    current, 
102 

welded  joints,  91 

welds,  140 

cast  iron  welds,  131 

resistance  welds,  389 

—  weld  (arc),  definition  of,  116 

—  of  welded  joints,  135 

Stresses    in    arc    welded   joints,    92, 

*93 

— ,  result  of  ' '  locked-in, ' '  62 
Strip  welding  jig,  *376 
Strohmenger-Slaughter   process,   the, 

1,3 
Structure    of    arc    deposited    metal, 

*105,  *106 

electrolytic     iron,     character- 
istic, *199 

Studies  in  overlap  and  penetration, 
*56 


INDEX 


415 


Studs,  use  of,  in  arc  welding,  129, 
?130,  *133,  144,  155 

Successful  welds,  reason  for,  138 

Summary  of  the  results  of  the  study 
of  the  metallography  of  arc-fused 
steel,  212 

Supervision  of  arc  welders,  145 

Surface,  building  up  a,  with  the 
carbon  arc,  *72 

Suspended  head  spot-welding  ma- 
chine, 294 

Swinging  bracket  support  for  spot- 
welding  work,  *288,  *292 

Swivel  head,  portable  spot-welding 
machine,  *293 

Symbols,  combination  arc  welding, 
118,  *119,  *120,  *121,  *122, 
*123,  *124,  *125,  *126 

—  used  in  arc  welding,  109 


"Tack,"  meaning  of,  63 

Tack  weld    (arc),  definition  of,  115 

Tank,   corrugated   steel,  welding  by 

machine,  *236,  237 
— ,    how  edges  of,  are  welded,  237 

—  seam,  welded  straight,  *222 
Tanks,  arc  welded,  *137 
Taper  of  carbon-electrode,   68 
Taps,  method  of  welding  broken,  to 

remove  from  hole,  *149 
— ,  removing  broken  taps,  150 
Taylor    cross-current    spot    welding 

process,  *8 

—  spot-welding      machines,       *302, 

*303 

—  Welder  Co.,  303 

Teapot  spout,  a  finish  welded,  *380 

welding  jig,   *380 

Tee  weld  (arc),  definition  of,  112 
Tensile  properties  of  electrodes,  179, 

180,  181 
Tension    specimen,    appearance    of, 

after  test,  *183 
Terminology,  a  brief,  63 
Terms,  elementary  electrical,  398 
Terrell  Equipment  Co.,  296 


Test  blocks,  formation  of,  for  arc- 
fused  metal,  *175,  176 

Tests,  the  Wirt-Jones,  on  arc  welds, 
189 

Thermal  analysis  of  arc-fused  steel, 
210 

—  characteristics  of  arc-fused  iron, 

210,  *211 
Thickness  and  weight  of  sheet  iron 

and  steel,  321,  322 
Thomson      butt-welding      machines, 

*240,    *241,   *244,   *245,    *246, 

*251,    *254,   *256,   *345,    *347, 

*348,   *351 

—  Co.'s  tests  on  butt- welds,  395 
spot  welds,  391 

—  Electric  Welding  Co.,  366,  395 
— ,  Elihu,  4 

—  foot-,  automatic-,  and  hand-oper- 

ated     spot-welding     machines, 
280 

—  seam-welding      machines,      *367, 

*369,    *370,    *373,    *374,    *375, 
*376,   *377 

—  spot-welding  machines,  *226, 

*227,    *281,    *282,   *283,    *284, 
*285,    *286,    *287,    *288 

—  vertical  mash  welding  machines, 

*358,  *359,  *360 

Three-roller     boiler     tube     machine, 
•   *332 

Thum,  E.  E.,  396 

Time  required  to  cut  with  the  car- 
bon arc,  78,  79,  80 
Tit  or  projection  method  of  welding, 

*291 

Topeka  shops  of  the  Santa  Fe  Kail- 
road,  339 

Tool  parts  arranged  for  welding, 
*354,  *355,  *357,  *361, 
*364 

,  grooving   to    aid   in   welding, 

*364 

—  room  butt-welding  machine,  *261 

—  welding,    the    insert    method    of, 

355 

Tools,  butt -welding,  *350,  *352,  *354 
Training  arc  welders,  47,  145 


416 


INDEX 


Transformer    of    butt-welding    ma- 
chine, 239,  *240 
Truscon  Steel  Co.,  397 
Tube  rollers,  boiler,  *331,  *332,  *334, 
*341 

—  welding    machine    with    built-on 

rolling     device,      *334,     *339, 
*340,  *341 

—  -welding     set     for     butt-welding 

work,'*263 

—  work,  examples  of,  *88 

Tubes,  boiler,  pressure  required  for 

welding,  337 

— ,  — ,  ready  for  flash  weld,  *329 
Tubing     automatically     arc-welded, 

*233 
Tungsten    ring    machine    arc-welded 

to  cold  rolled  core,  *232 
T-welding,  252 

Twist-drill  blanks  just  welded,  *349 
Two-spot  welding  machine  with  ro- 

tatable  head,  298,  *299 
Typical  ammeter  charts  of  operation 
of    Morton    arc    welding    ma- 
chine, *224 

—  examples    of    prepared    and    fin- 

ished   arc   welding   work,    *87, 
*88,  *89 

-  light  spot-welding  machine,  *278 
Types  of  welding  outfits,  21 

U 

United    Traction    Co.,    shop    repair 

work  of,  150 
Universal     spot-welding     die-points, 

*296,  *297,  *298 
Unland,  H.  L.,  214 
Unsoundness  of  arc-fused  metal, 

microscopic  evidence  of,  193 
Uealite  crucible,  208 
Using  a  flux  for  flue  welding,  330 
U.  S.  Light  and  Heat  Co.,  40 
portable  a-c,  motor- 
generator       set, 
*39,  40 


Van  Bibber,  P.  T.,  324 


Vertical    mash    welding    machines, 
*358,  *359,  *360 

—  position    defined    as    applied    to 

ship  work,  *114,  115 

—  seam  welding,  62 
Volt,  what  is  a,  398 

Voltage,  effect  of,  on  arc  welds,  1G9 
Voltex  process,  the,  2 
Vulcan  Iron  Works,  repair  of  large 
crankshaft  by,  162 


W 

Wagner,  167,  169 

Wanamaker,  E.,  84 

Warping  of  parent  metal  caused  by 

deposit  contraction,  *59 
Water-cooled     die-points     for     spot 

welding,    *281,    *283,    *284,    *286, 

*288,  *291,  *296,  *297,  *298,  *302, 

*303 

''Water-pail"  forge,  the,  1,  3 
Watt,  what  is  a,  398 
"Weaving,"  meaning  of,  64 

—  of  arc,  52 
Weed,  J.  M.,  311 

Weight  of  sheet  iron  and  steel,  322 
Welded  and  riveted  joints,  *389,  391 

—  automobile  hub   stampings,   *2'2l 

—  rear  axle  housing,  *222 
Welder,  points  for  the,  to  learn,  49 
Welding  boiler  tubes  by  the  electric 

resistance  process,  324 

—  booth,  48 

—  Committee     electrodes,     composi- 

tion of,  107 

the  Emergency  Fleet  Corpor- 
ation, 90,  104,  107,  109, 
134 

—  high-speed    to    low-carbon    steel, 

344 

—  Mild  Steel,  paper  on,  223 

—  other  than  round  tools,  354 
-  pipe  coils,   *256 

—  rotor    bars    to    end    rings    in    a 

special    butt-welding    machine, 
263 

—  Stellite,  356 


INDEX 


417 


Welding    valve    elbows    on    Liberty 

motor  cylinders,  *268 
Welds,  arc,  the  Wirt-Jones  tests  on, 

189 
— ,  good  and  bad  arc,  *100 

—  showing    poor    and    good    fusion, 

*60 

— ,  terms  and  symbols  for  arc,  109 

' '  Welt, ' '  meaning  of,  64 

Weltrodes,  composition  of,  86 

— ,  sizes  of,  87 

Westinghouse  Electric  and  Mfg.  Co., 
38,  47,  66,  81,  269 

— •»  single-operator   portable   welding 
set,  *38 

Wheel,  car,  repairs,  *157,  *158 

Wilson  two-arc  "plastic  arc'"  weld- 
ing set,  *33 

-  Welder  and   Metals   Co.,   33,   81, 
88,  128 

—  welding   and   cutting   panel,   *34 


Winfield       butt-welding       machines, 

*257,  *259,  260,  *261 
-  Electric    Welding    Machine    Co., 
260,  295 

—  spot-welding       machines,       *291, 

*292,  *293,  *294,  *295 
Wire    to    use    to    connect    up    seam 

welding  machines,  379 
Wiring  diagram  for  percussive  weld- 
ing, *271 

Wirt-Jones  arc  weld  tests,   189 
Work   clamps   for  butt-welding  ma- 
chines, *242,  *243,  *257 
Worn    and    repaired    crane    wheels, 
*221 

—  motor    shaft    built    up    by    auto- 

matic    arc     welding    machine, 

*220 

Z 

Zerner  process,  the,  1,  *2 
Zeus  arc-welding  outfit,  *42 


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